chunk.c

/*
 * This file and its contents are licensed under the Apache License 2.0.
 * Please see the included NOTICE for copyright information and
 * LICENSE-APACHE for a copy of the license.
 */
#include <postgres.h>
#include <access/genam.h>
#include <access/htup.h>
#include <access/htup_details.h>
#include <access/reloptions.h>
#include <access/table.h>
#include <access/tableam.h>
#include <access/tupdesc.h>
#include <access/xact.h>
#include <catalog/indexing.h>
#include <catalog/namespace.h>
#include <catalog/pg_attribute.h>
#include <catalog/pg_class.h>
#include <catalog/pg_constraint.h>
#include <catalog/pg_inherits.h>
#include <catalog/pg_opfamily.h>
#include <catalog/pg_publication.h>
#include <catalog/pg_publication_rel_d.h>
#include <catalog/pg_trigger.h>
#include <catalog/pg_type.h>
#include <catalog/pg_type_d.h>
#include <catalog/toasting.h>
#include <commands/defrem.h>
#include <commands/publicationcmds.h>
#include <commands/tablecmds.h>
#include <commands/trigger.h>
#include <executor/executor.h>
#include <fmgr.h>
#include <foreign/fdwapi.h>
#include <funcapi.h>
#include <miscadmin.h>
#include <nodes/execnodes.h>
#include <nodes/lockoptions.h>
#include <nodes/makefuncs.h>
#include <nodes/value.h>
#include <parser/parse_node.h>
#include <storage/lmgr.h>
#include <storage/lockdefs.h>
#include <tcop/tcopprot.h>
#include <ts_stats/ts_stats_record.h>
#include <utils/acl.h>
#include <utils/array.h>
#include <utils/builtins.h>
#include <utils/datum.h>
#include <utils/elog.h>
#include <utils/fmgroids.h>
#include <utils/hsearch.h>
#include <utils/inval.h>
#include <utils/lsyscache.h>
#include <utils/palloc.h>
#include <utils/syscache.h>
#include <utils/timestamp.h>
#include <utils/typcache.h>

#include "chunk.h"

#include "compat/compat.h"
#include "bgw_policy/chunk_stats.h"
#include "cache.h"
#include "chunk_index.h"

#include "cross_module_fn.h"
#include "debug_assert.h"
#include "debug_point.h"
#include "dimension.h"
#include "dimension_slice.h"
#include "dimension_vector.h"
#include "errors.h"
#include "foreign_key.h"
#include "guc.h"
#include "hypercube.h"
#include "hypertable.h"
#include "hypertable_cache.h"
#include "osm_callbacks.h"
#include "partition_chunk.h"
#include "process_utility.h"
#include "scan_iterator.h"
#include "scanner.h"
#include "time_utils.h"
#include "trigger.h"
#include "ts_catalog/catalog.h"
#include "ts_catalog/chunk_column_stats.h"
#include "ts_catalog/chunk_rewrite.h"
#include "ts_catalog/compression_chunk_size.h"
#include "ts_catalog/compression_settings.h"
#include "ts_catalog/continuous_agg.h"
#include "ts_catalog/continuous_aggs_watermark.h"
#include "utils.h"

TS_FUNCTION_INFO_V1(ts_chunk_show_chunks);
TS_FUNCTION_INFO_V1(ts_chunk_drop_chunks);
TS_FUNCTION_INFO_V1(ts_chunk_drop_single_chunk);
TS_FUNCTION_INFO_V1(ts_chunk_attach_osm_table_chunk);
TS_FUNCTION_INFO_V1(ts_chunk_drop_osm_chunk);
TS_FUNCTION_INFO_V1(ts_chunk_id_from_relid);
TS_FUNCTION_INFO_V1(ts_chunk_show);
TS_FUNCTION_INFO_V1(ts_chunk_create);
TS_FUNCTION_INFO_V1(ts_chunk_status);

static bool ts_chunk_add_status(Chunk *chunk, int32 status);

static const char *
DatumGetRegClassString(Datum datum)
{
	return DatumGetCString(DirectFunctionCall1(regclassout, datum));
}

/* Used when processing scanned chunks */
typedef enum ChunkResult
{
	CHUNK_DONE,
	CHUNK_IGNORED,
	CHUNK_PROCESSED
} ChunkResult;

/*
 * Context for scanning and building a chunk from a stub.
 *
 * If found, the chunk will be created and the chunk pointer member is set in
 * the result. Optionally, a caller can pre-allocate the chunk member's memory,
 * which is useful if one, e.g., wants to fill in an memory-aligned array of
 * chunks.
 *
 */
typedef struct ChunkStubScanCtx
{
	ChunkStub *stub;
	Chunk *chunk;
	LOCKMODE chunk_lockmode;
	const ScanTupLock *slice_lock;
} ChunkStubScanCtx;

typedef ChunkResult (*on_chunk_stub_func)(ChunkScanCtx *ctx, ChunkStub *stub);
static void chunk_scan_ctx_init(ChunkScanCtx *ctx, const Hypertable *ht, const Point *point);
static void chunk_scan_ctx_destroy(ChunkScanCtx *ctx);
static void chunk_collision_scan(ChunkScanCtx *scanctx, const Hypercube *cube);
static int chunk_scan_ctx_foreach_chunk_stub(ChunkScanCtx *ctx, on_chunk_stub_func on_chunk,
											 uint64 limit);
static Datum show_chunks_return_srf(FunctionCallInfo fcinfo);
static int chunk_cmp(const void *ch1, const void *ch2);
static void init_scan_by_relid(ScanIterator *iterator, Oid relid);
static Chunk *get_chunks_in_time_range(Hypertable *ht, int64 older_than, int64 newer_than,
									   MemoryContext mctx, uint64 *num_chunks_returned,
									   ScanTupLock *tuplock);
static Chunk *get_chunks_in_creation_time_range(Hypertable *ht, int64 older_than, int64 newer_than,
												MemoryContext mctx, uint64 *num_chunks_returned,
												ScanTupLock *tupLock);

static HeapTuple
chunk_formdata_make_tuple(const FormData_chunk *fd, TupleDesc desc)
{
	Datum values[Natts_chunk];
	bool nulls[Natts_chunk] = { false };

	Assert(OidIsValid(fd->relid));

	memset(values, 0, sizeof(Datum) * Natts_chunk);

	values[AttrNumberGetAttrOffset(Anum_chunk_id)] = Int32GetDatum(fd->id);
	values[AttrNumberGetAttrOffset(Anum_chunk_hypertable_id)] = Int32GetDatum(fd->hypertable_id);
	values[AttrNumberGetAttrOffset(Anum_chunk_status)] = Int32GetDatum(fd->status);
	values[AttrNumberGetAttrOffset(Anum_chunk_osm_chunk)] = BoolGetDatum(fd->osm_chunk);
	values[AttrNumberGetAttrOffset(Anum_chunk_creation_time)] = Int64GetDatum(fd->creation_time);
	values[AttrNumberGetAttrOffset(Anum_chunk_relid)] = ObjectIdGetDatum(fd->relid);

	return heap_form_tuple(desc, values, nulls);
}

void
ts_chunk_formdata_fill(FormData_chunk *fd, const TupleInfo *ti)
{
	bool should_free;
	HeapTuple tuple = ts_scanner_fetch_heap_tuple(ti, false, &should_free);

	/*
	 * Every chunk column is fixed-length and NOT NULL, and the catalog table is
	 * rebuilt rather than altered on upgrade, so a stored tuple always holds all
	 * of its attributes. We can therefore copy the form directly.
	 */
	Assert(HeapTupleHeaderGetNatts(tuple->t_data) == Natts_chunk);
	*fd = *(Form_chunk) GETSTRUCT(tuple);

	if (should_free)
	{
		heap_freetuple(tuple);
	}
}

/*
 * A chunk's schema and table name are not stored in the catalog; they are
 * looked up from the chunk relation on demand.
 */
char *
ts_chunk_get_schema_name(const Chunk *chunk)
{
	return get_namespace_name(get_rel_namespace(chunk->fd.relid));
}

char *
ts_chunk_get_table_name(const Chunk *chunk)
{
	return get_rel_name(chunk->fd.relid);
}

int64
ts_chunk_primary_dimension_start(const Chunk *chunk)
{
	return chunk->cube->slices[0]->fd.range_start;
}

int64
ts_chunk_primary_dimension_end(const Chunk *chunk)
{
	return chunk->cube->slices[0]->fd.range_end;
}

static void
chunk_insert_relation(Relation rel, const Chunk *chunk)
{
	HeapTuple new_tuple;
	CatalogSecurityContext sec_ctx;
	FormData_chunk fd = chunk->fd;

	new_tuple = chunk_formdata_make_tuple(&fd, RelationGetDescr(rel));

	ts_catalog_database_info_become_owner(ts_catalog_database_info_get(), &sec_ctx);
	ts_catalog_insert(rel, new_tuple);
	ts_catalog_restore_user(&sec_ctx);

	heap_freetuple(new_tuple);
}

void
ts_chunk_insert_lock(const Chunk *chunk, LOCKMODE lock)
{
	Catalog *catalog = ts_catalog_get();
	Relation rel;

	rel = table_open(catalog_get_table_id(catalog, CHUNK), lock);
	chunk_insert_relation(rel, chunk);
	table_close(rel, lock);
}

typedef struct CollisionInfo
{
	Hypercube *cube;
	ChunkStub *colliding_chunk;
} CollisionInfo;

/*-
 * Align a chunk's hypercube in 'aligned' dimensions.
 *
 * Alignment ensures that chunks line up in a particular dimension, i.e., their
 * ranges should either be identical or not overlap at all.
 *
 * Non-aligned:
 *
 * ' [---------]      <- existing slice
 * '      [---------] <- calculated (new) slice
 *
 * To align the slices above there are two cases depending on where the
 * insertion point happens:
 *
 * Case 1 (reuse slice):
 *
 * ' [---------]
 * '      [--x------]
 *
 * The insertion point x falls within the range of the existing slice. We should
 * reuse the existing slice rather than creating a new one.
 *
 * Case 2 (cut to align):
 *
 * ' [---------]
 * '      [-------x-]
 *
 * The insertion point falls outside the range of the existing slice and we need
 * to cut the new slice to line up.
 *
 * ' [---------]
 * '        cut [---]
 * '
 *
 * Note that slice reuse (case 1) happens already when calculating the tentative
 * hypercube for the chunk, and is thus already performed once reaching this
 * function. Thus, we deal only with case 2 here. Also note that a new slice
 * might overlap in complicated ways, requiring multiple cuts. For instance,
 * consider the following situation:
 *
 * ' [------]   [-] [---]
 * '      [---x-------]  <- calculated slice
 *
 * This should but cut-to-align as follows:
 *
 * ' [------]   [-] [---]
 * '         [x]
 *
 * After a chunk collision scan, this function is called for each chunk in the
 * chunk scan context. Chunks in the scan context may have only a partial set of
 * slices if they only overlap in some, but not all, dimensions (see
 * illustrations below). Still, partial chunks may still be of interest for
 * alignment in a particular dimension. Thus, if a chunk has an overlapping
 * slice in an aligned dimension, we cut to not overlap with that slice.
 */
static ChunkResult
do_dimension_alignment(ChunkScanCtx *scanctx, ChunkStub *stub)
{
	CollisionInfo *info = scanctx->data;
	Hypercube *cube = info->cube;
	const Hyperspace *space = scanctx->ht->space;
	ChunkResult res = CHUNK_IGNORED;
	int i;

	for (i = 0; i < space->num_dimensions; i++)
	{
		const Dimension *dim = &space->dimensions[i];
		const DimensionSlice *chunk_slice;
		DimensionSlice *cube_slice;
		int64 coord = scanctx->point->coordinates[i];

		if (!dim->fd.aligned)
		{
			continue;
		}

		/*
		 * The stub might not have a slice for each dimension, so we cannot
		 * use array indexing. Fetch slice by dimension ID instead.
		 */
		chunk_slice = ts_hypercube_get_slice_by_dimension_id(stub->cube, dim->fd.id);

		if (NULL == chunk_slice)
		{
			continue;
		}

		cube_slice = cube->slices[i];

		/*
		 * Only cut-to-align if the slices collide and are not identical
		 * (i.e., if we are reusing an existing slice we should not cut it)
		 */
		if (!ts_dimension_slices_equal(cube_slice, chunk_slice) &&
			ts_dimension_slices_collide(cube_slice, chunk_slice))
		{
			ts_dimension_slice_cut(cube_slice, chunk_slice, coord);
			res = CHUNK_PROCESSED;
		}
	}

	return res;
}

/*
 * Resolve chunk collisions.
 *
 * After a chunk collision scan, this function is called for each chunk in the
 * chunk scan context. We only care about chunks that have a full set of
 * slices/constraints that overlap with our tentative hypercube, i.e., they
 * fully collide. We resolve those collisions by cutting the hypercube.
 */
static ChunkResult
do_collision_resolution(ChunkScanCtx *scanctx, ChunkStub *stub)
{
	CollisionInfo *info = scanctx->data;
	Hypercube *cube = info->cube;
	const Hyperspace *space = scanctx->ht->space;
	ChunkResult res = CHUNK_IGNORED;
	int i;

	if (stub->cube->num_slices != space->num_dimensions || !ts_hypercubes_collide(cube, stub->cube))
	{
		return CHUNK_IGNORED;
	}

	for (i = 0; i < space->num_dimensions; i++)
	{
		DimensionSlice *cube_slice = cube->slices[i];
		DimensionSlice *chunk_slice = stub->cube->slices[i];
		int64 coord = scanctx->point->coordinates[i];

		/*
		 * Only cut if we aren't reusing an existing slice and there is a
		 * collision
		 */
		if (!ts_dimension_slices_equal(cube_slice, chunk_slice) &&
			ts_dimension_slices_collide(cube_slice, chunk_slice))
		{
			ts_dimension_slice_cut(cube_slice, chunk_slice, coord);
			res = CHUNK_PROCESSED;

			/*
			 * Redo the collision check after each cut since cutting in one
			 * dimension might have resolved the collision in another
			 */
			if (!ts_hypercubes_collide(cube, stub->cube))
			{
				return res;
			}
		}
	}

	Assert(!ts_hypercubes_collide(cube, stub->cube));

	return res;
}

static ChunkResult
check_for_collisions(ChunkScanCtx *scanctx, ChunkStub *stub)
{
	CollisionInfo *info = scanctx->data;
	Hypercube *cube = info->cube;
	const Hyperspace *space = scanctx->ht->space;

	/* Check if this chunk collides with our hypercube */
	if (stub->cube->num_slices == space->num_dimensions && ts_hypercubes_collide(cube, stub->cube))
	{
		info->colliding_chunk = stub;
		return CHUNK_DONE;
	}

	return CHUNK_IGNORED;
}

/*
 * Check if a (tentative) chunk collides with existing chunks.
 *
 * Return the colliding chunk. Note that the chunk is a stub and not a full
 * chunk.
 */
static ChunkStub *
chunk_collides(const Hypertable *ht, const Hypercube *hc)
{
	ChunkScanCtx scanctx;
	CollisionInfo info = {
		.cube = (Hypercube *) hc,
		.colliding_chunk = NULL,
	};

	chunk_scan_ctx_init(&scanctx, ht, NULL);

	/* Scan for all chunks that collide with the hypercube of the new chunk */
	chunk_collision_scan(&scanctx, hc);
	scanctx.data = &info;

	/* Find chunks that collide */
	chunk_scan_ctx_foreach_chunk_stub(&scanctx, check_for_collisions, 0);

	chunk_scan_ctx_destroy(&scanctx);

	return info.colliding_chunk;
}

/*-
 * Resolve collisions and perform alignment.
 *
 * Chunks collide only if their hypercubes overlap in all dimensions. For
 * instance, the 2D chunks below collide because they overlap in both the X and
 * Y dimensions:
 *
 * ' _____
 * ' |    |
 * ' | ___|__
 * ' |_|__|  |
 * '   |     |
 * '   |_____|
 *
 * While the following chunks do not collide, although they still overlap in the
 * X dimension:
 *
 * ' _____
 * ' |    |
 * ' |    |
 * ' |____|
 * '   ______
 * '   |     |
 * '   |    *|
 * '   |_____|
 *
 * For the collision case above we obviously want to cut our hypercube to no
 * longer collide with existing chunks. However, the second case might still be
 * of interest for alignment in case X is an 'aligned' dimension. If '*' is the
 * insertion point, then we still want to cut the hypercube to ensure that the
 * dimension remains aligned, like so:
 *
 * ' _____
 * ' |    |
 * ' |    |
 * ' |____|
 * '       ___
 * '       | |
 * '       |*|
 * '       |_|
 *
 *
 * We perform alignment first as that might actually resolve chunk
 * collisions. After alignment we check for any remaining collisions.
 */
static void
chunk_collision_resolve(const Hypertable *ht, Hypercube *cube, const Point *p)
{
	ChunkScanCtx scanctx;
	CollisionInfo info = {
		.cube = cube,
		.colliding_chunk = NULL,
	};

	chunk_scan_ctx_init(&scanctx, ht, p);

	/* Scan for all chunks that collide with the hypercube of the new chunk */
	chunk_collision_scan(&scanctx, cube);
	scanctx.data = &info;

	/* Cut the hypercube in any aligned dimensions */
	chunk_scan_ctx_foreach_chunk_stub(&scanctx, do_dimension_alignment, 0);

	/*
	 * If there are any remaining collisions with chunks, then cut-to-fit to
	 * resolve those collisions
	 */
	chunk_scan_ctx_foreach_chunk_stub(&scanctx, do_collision_resolution, 0);

	chunk_scan_ctx_destroy(&scanctx);
}

/* applies the attributes and statistics target for columns on the hypertable
   to columns on the chunk */
static void
set_attoptions(Relation ht_rel, Oid chunk_oid)
{
	TupleDesc tupleDesc = RelationGetDescr(ht_rel);
	int natts = tupleDesc->natts;
	int attno;
	List *alter_cmds = NIL;

	for (attno = 1; attno <= natts; attno++)
	{
		Form_pg_attribute attribute = TupleDescAttr(tupleDesc, attno - 1);
		char *attributeName = NameStr(attribute->attname);
		HeapTuple tuple;
		Datum options;
		bool isnull;

		/* Ignore dropped */
		if (attribute->attisdropped)
		{
			continue;
		}

		tuple = SearchSysCacheAttName(RelationGetRelid(ht_rel), attributeName);

		Assert(tuple != NULL);

		/*
		 * Pass down the attribute options (ALTER TABLE ALTER COLUMN SET
		 * attribute_option)
		 */
		options = SysCacheGetAttr(ATTNAME, tuple, Anum_pg_attribute_attoptions, &isnull);

		if (!isnull)
		{
			AlterTableCmd *cmd = makeNode(AlterTableCmd);

			cmd->subtype = AT_SetOptions;
			cmd->name = attributeName;
			cmd->def = (Node *) untransformRelOptions(options);
			alter_cmds = lappend(alter_cmds, cmd);
		}

		/*
		 * Pass down the attribute options (ALTER TABLE ALTER COLUMN SET
		 * STATISTICS)
		 */
		options = SysCacheGetAttr(ATTNAME, tuple, Anum_pg_attribute_attstattarget, &isnull);
		if (!isnull)
		{
			int32 target = DatumGetInt32(options);

			/* Don't do anything if it's set to the default */
			if (target != -1)
			{
				AlterTableCmd *cmd = makeNode(AlterTableCmd);

				cmd->subtype = AT_SetStatistics;
				cmd->name = attributeName;
				cmd->def = (Node *) makeInteger(target);
				alter_cmds = lappend(alter_cmds, cmd);
			}
		}

		ReleaseSysCache(tuple);
	}

	if (alter_cmds != NIL)
	{
		AlterTableInternal(chunk_oid, alter_cmds, false);
		list_free_deep(alter_cmds);
	}
}

static void
create_toast_table(CreateStmt *stmt, Oid chunk_oid)
{
	/* similar to tcop/utility.c */
#if PG18_LT
	char *validnsps[] = HEAP_RELOPT_NAMESPACES;
#else
	const char *const validnsps[] = HEAP_RELOPT_NAMESPACES;
#endif
	Datum toast_options =
		transformRelOptions(UnassignedDatum, stmt->options, "toast", validnsps, true, false);

	(void) heap_reloptions(RELKIND_TOASTVALUE, toast_options, true);

	NewRelationCreateToastTable(chunk_oid, toast_options);
}

static void
copy_hypertable_acl_to_relid(const Hypertable *ht, const Oid owner_id, const Oid relid)
{
	ts_copy_relation_acl(ht->main_table_relid, relid, owner_id);
}

/*
 * Create a chunk's table.
 *
 * A chunk inherits from the main hypertable and will have the same owner. Since
 * chunks can be created either in the TimescaleDB internal schema or in a
 * user-specified schema, some care has to be taken to use the right
 * permissions, depending on the case:
 *
 * 1. if the chunk is created in the internal schema, we create it as the
 * catalog/schema owner (i.e., anyone can create chunks there via inserting into
 * a hypertable, but can not do it via CREATE TABLE).
 *
 * 2. if the chunk is created in a user-specified "associated schema", then we
 * shouldn't use the catalog owner to create the table since that typically
 * implies super-user permissions. If we would allow that, anyone can specify
 * someone else's schema in create_hypertable() and create chunks in it without
 * having the proper permissions to do so. With this logic, the hypertable owner
 * must have permissions to create tables in the associated schema, or else
 * table creation will fail. If the schema doesn't yet exist, the table owner
 * instead needs the proper permissions on the database to create the schema.
 */
Oid
ts_chunk_create_table(const Chunk *chunk, const Hypertable *ht, const char *schema_name,
					  const char *table_name, const char *tablespacename)
{
	Relation rel;
	ObjectAddress address;
	int sec_ctx;
	char *amname = NULL;

	amname = get_am_name(ts_get_rel_am(chunk->hypertable_relid));

	/*
	 * CreateStmt node to create the chunk table
	 */
	CreateStmt stmt = {
		.type = T_CreateStmt,
		.relation = makeRangeVar((char *) schema_name, (char *) table_name, 0),
		.tablespacename = tablespacename ? (char *) tablespacename : NULL,
		.options =
			(chunk->relkind == RELKIND_RELATION) ? ts_get_reloptions(ht->main_table_relid) : NIL,
		.accessMethod = amname,
	};

	/*
	 * If partitioned hypertables are enabled, create the chunk as a standalone
	 * table with the same columns as the hypertable to attach it as a partition
	 * later. Otherwise, create it as an inherited table.
	 */
	if (is_partitioning_allowed(ht->main_table_relid))
	{
		List *attlist = NIL;
		List *constraints = NIL;
		ts_partition_chunk_prepare_attributes(ht->main_table_relid, &attlist, &constraints);
		stmt.tableElts = attlist;
		stmt.constraints = constraints;
	}
	else
	{
		stmt.inhRelations = list_make1(makeRangeVar((char *) NameStr(ht->fd.schema_name),
													(char *) NameStr(ht->fd.table_name),
													0));
	}

	Oid uid, saved_uid;

	Assert(chunk->hypertable_relid == ht->main_table_relid);

	rel = table_open(ht->main_table_relid, AccessShareLock);

	/* Inherit the persistence (LOGGED or UNLOGGED) from the parent hypertable */
	stmt.relation->relpersistence = rel->rd_rel->relpersistence;

	/*
	 * If the chunk is created in the internal schema, become the catalog
	 * owner, otherwise become the hypertable owner
	 */
	if (strcmp(schema_name, INTERNAL_SCHEMA_NAME) == 0)
	{
		uid = ts_catalog_database_info_get()->owner_uid;
	}
	else
	{
		uid = rel->rd_rel->relowner;
	}

	GetUserIdAndSecContext(&saved_uid, &sec_ctx);

	if (uid != saved_uid)
	{
		SetUserIdAndSecContext(uid, sec_ctx | SECURITY_LOCAL_USERID_CHANGE);
	}

	/* Prepare event trigger state and invoke ddl_command_start triggers */
	if (ts_guc_enable_event_triggers)
	{
		EventTriggerBeginCompleteQuery();
		EventTriggerDDLCommandStart((Node *) &stmt);
	}

	address = DefineRelation(&stmt, chunk->relkind, rel->rd_rel->relowner, NULL, NULL);

	/* Invoke ddl_command_end triggers and clean up the event trigger state */
	if (ts_guc_enable_event_triggers)
	{
		EventTriggerCollectSimpleCommand(address, InvalidObjectAddress, (Node *) &stmt);
		EventTriggerDDLCommandEnd((Node *) &stmt);
		EventTriggerEndCompleteQuery();
	}

	/* Make the newly defined relation visible so that we can update the
	 * ACL. */
	CommandCounterIncrement();

	/* Copy acl from hypertable to chunk relation record */
	copy_hypertable_acl_to_relid(ht, rel->rd_rel->relowner, address.objectId);

	if (chunk->relkind == RELKIND_RELATION)
	{
		/*
		 * need to create a toast table explicitly for some of the option
		 * setting to work
		 */
		create_toast_table(&stmt, address.objectId);

		/*
		 * Some options require being table owner to set for example statistics
		 * so we have to set them before restoring security context
		 */
		set_attoptions(rel, address.objectId);

		if (uid != saved_uid)
		{
			SetUserIdAndSecContext(saved_uid, sec_ctx);
		}
	}
	else
	{
		elog(ERROR, "invalid relkind \"%c\" when creating chunk", chunk->relkind);
	}

	/* Insert the table into the cache to attach it as partition later */
	if (is_partitioning_allowed(ht->main_table_relid))
	{
		ts_partition_cache_insert_chunk(ht, address.objectId);
	}

	table_close(rel, AccessShareLock);

	return address.objectId;
}

static int32
get_next_chunk_id()
{
	int32 chunk_id;
	CatalogSecurityContext sec_ctx;
	const Catalog *catalog = ts_catalog_get();

	ts_catalog_database_info_become_owner(ts_catalog_database_info_get(), &sec_ctx);
	chunk_id = ts_catalog_table_next_seq_id(catalog, CHUNK);
	ts_catalog_restore_user(&sec_ctx);

	return chunk_id;
}

/*
 * Stamp the chunk_id on every cube slice
 */
static void
prepare_cube_slices_for_chunk(Hypercube *cube, int32 chunk_id)
{
	Assert(chunk_id > 0);

	for (int i = 0; i < cube->num_slices; i++)
	{
		cube->slices[i]->fd.id = 0;
		cube->slices[i]->fd.chunk_id = chunk_id;
	}
}

/*
 * Pick a table name for a new chunk. The table name can be given explicitly, or
 * generated from the hypertable's associated table prefix and the chunk id if
 * table_name is NULL.
 */
static char *
chunk_choose_table_name(const Hypertable *ht, int32 chunk_id, const char *table_name)
{
	if (NULL == table_name || table_name[0] == '\0')
	{
		const char *prefix = NameStr(ht->fd.associated_table_prefix);
		char *name = psprintf("%s_%d_chunk", prefix, chunk_id);

		if (strlen(name) >= NAMEDATALEN)
		{
			ereport(ERROR, (errcode(ERRCODE_NAME_TOO_LONG), errmsg("chunk table name too long")));
		}

		return name;
	}

	return pstrdup(table_name);
}

/*
 * Create a chunk object from the dimensional constraints in the given hypercube.
 *
 * The chunk object is then used to create the actual chunk table and update the
 * metadata separately.
 */
static Chunk *
chunk_create_object(const Hypertable *ht, Hypercube *cube, int32 chunk_id)
{
	const Hyperspace *hs = ht->space;

	/* Create a new chunk based on the hypercube */
	Chunk *chunk = ts_chunk_create_base(chunk_id);

	chunk->fd.hypertable_id = hs->hypertable_id;
	chunk->cube = cube;
	chunk->hypertable_relid = ht->main_table_relid;

	return chunk;
}

/*
 * Ensure the replica identity setting of a chunk matches that of the root
 * table.
 */
static void
chunk_set_replica_identity(const Chunk *chunk)
{
	Relation ht_rel = relation_open(chunk->hypertable_relid, AccessShareLock);
	Relation ch_rel = relation_open(chunk->fd.relid, AccessShareLock);

	/* Do nothing if REPLICA IDENTITY of hypertable and chunk are equal */
	if (ht_rel->rd_rel->relreplident == ch_rel->rd_rel->relreplident)
	{
		table_close(ch_rel, NoLock);
		table_close(ht_rel, NoLock);
		return;
	}

	ReplicaIdentityStmt stmt = {
		.type = T_ReplicaIdentityStmt,
		.identity_type = ht_rel->rd_rel->relreplident,
	};
	AlterTableCmd cmd = {
		.type = T_AlterTableCmd,
		.def = (Node *) &stmt,
		.subtype = AT_ReplicaIdentity,
	};
	CatalogSecurityContext sec_ctx;

	if (stmt.identity_type == REPLICA_IDENTITY_INDEX)
	{
		/* Use RelationGetReplicaIndex() instead of rd_replidindex
		 * directly to ensure the index list is loaded after any
		 * relcache invalidation. */
		Oid ht_indexoid = RelationGetReplicaIndex(ht_rel);
		Oid chunk_index_relid = InvalidOid;

		if (OidIsValid(ht_indexoid))
		{
			chunk_index_relid = ts_chunk_index_get_by_hypertable_indexrelid(ch_rel, ht_indexoid);
		}

		if (OidIsValid(chunk_index_relid))
		{
			stmt.name = get_rel_name(chunk_index_relid);
		}
		else
		{
			stmt.identity_type = REPLICA_IDENTITY_NOTHING;
		}
	}

	ts_catalog_database_info_become_owner(ts_catalog_database_info_get(), &sec_ctx);
	ts_alter_table_with_event_trigger(chunk->fd.relid, NULL, list_make1(&cmd), false);
	ts_catalog_restore_user(&sec_ctx);
	table_close(ch_rel, NoLock);
	table_close(ht_rel, NoLock);
}

static void
chunk_create_table_constraints(const Hypertable *ht, const Chunk *chunk)
{
	/* Do not create any of these for partitioned hypertables */
	if (is_partitioning_allowed(ht->main_table_relid))
	{
		return;
	}

	/* Create the chunk's constraints, triggers, and indexes */
	ts_chunk_constraints_create(ht, chunk);

	if (chunk->relkind == RELKIND_RELATION && !IS_OSM_CHUNK(chunk))
	{
		ts_trigger_create_all_on_chunk(chunk);
		ts_chunk_index_create_all(chunk->fd.hypertable_id,
								  chunk->hypertable_relid,
								  chunk->fd.id,
								  chunk->fd.relid,
								  InvalidOid);

		chunk_set_replica_identity(chunk);
	}

	/* Copy FK constraints after indexes are created, since FK validation
	 * requires the supporting unique index to exist on the chunk. */
	ts_chunk_copy_referencing_fk(ht, chunk);
	ts_chunk_inherit_outbound_fk(ht, chunk);
}

static Oid
chunk_create_table(Chunk *chunk, const Hypertable *ht, const char *schema_name,
				   const char *table_name)
{
	/* Create the actual table relation for the chunk */
	const char *tablespace = ts_hypertable_select_tablespace_name(ht, chunk);

	chunk->fd.relid = ts_chunk_create_table(chunk, ht, schema_name, table_name, tablespace);

	Assert(OidIsValid(chunk->fd.relid));

	return chunk->fd.relid;
}

/*
 * Creates only a table for a chunk.
 * Either table name or chunk id needs to be provided.
 */
static Chunk *
chunk_create_only_table_after_lock(const Hypertable *ht, Hypercube *cube, const char *schema_name,
								   const char *table_name, int32 chunk_id)
{
	Assert(table_name != NULL || chunk_id != INVALID_CHUNK_ID);

	if (!schema_name || schema_name[0] == '\0')
	{
		schema_name = NameStr(ht->fd.associated_schema_name);
	}

	Chunk *chunk = chunk_create_object(ht, cube, chunk_id);
	char *chunk_table_name = chunk_choose_table_name(ht, chunk_id, table_name);

	chunk_create_table(chunk, ht, schema_name, chunk_table_name);

	return chunk;
}

static void
get_hypertable_publication_filters(Oid puboid, const Chunk *chunk, List **columns,
								   Node **whereClause)
{
	HeapTuple pubtuple;
	Datum datum;
	bool isnull;

	*columns = NIL;
	*whereClause = NULL;

	/* Get filters for hypertable, chunk should inherit them */
	pubtuple = SearchSysCache2(PUBLICATIONRELMAP,
							   ObjectIdGetDatum(chunk->hypertable_relid),
							   ObjectIdGetDatum(puboid));

	if (!HeapTupleIsValid(pubtuple))
	{
		return;
	}

	datum = SysCacheGetAttr(PUBLICATIONRELMAP, pubtuple, Anum_pg_publication_rel_prqual, &isnull);
	if (!isnull)
	{
		char *prqual_str = TextDatumGetCString(datum);
		*whereClause = stringToNode(prqual_str);
	}

	datum = SysCacheGetAttr(PUBLICATIONRELMAP, pubtuple, Anum_pg_publication_rel_prattrs, &isnull);
	if (!isnull)
	{
		ArrayType *arr = DatumGetArrayTypeP(datum);
		int nelems = ARR_DIMS(arr)[0];
		int16 *attnums = (int16 *) ARR_DATA_PTR(arr);

		for (int i = 0; i < nelems; i++)
		{
			char *colname = get_attname(chunk->hypertable_relid, attnums[i], false);
			*columns = lappend(*columns, makeString(colname));
		}
	}

	ReleaseSysCache(pubtuple);
}

static void
chunk_add_to_publication(Oid puboid, const Chunk *chunk)
{
	PublicationRelInfo pri = { 0 };
	Relation chunk_rel;
	List *columns = NIL;
	Node *whereClause = NULL;

	get_hypertable_publication_filters(puboid, chunk, &columns, &whereClause);

	chunk_rel = table_open(chunk->fd.relid, AccessShareLock);

	pri.relation = chunk_rel;
	pri.columns = columns;
	pri.whereClause = whereClause;

#if PG19_GE
	publication_add_relation(puboid, &pri, true, NULL);
#else
	publication_add_relation(puboid, &pri, true);
#endif

	table_close(chunk_rel, AccessShareLock);
}

static void
chunk_add_to_publications(const Chunk *chunk)
{
	List *puboids;
	ListCell *lc;

	puboids = GetRelationIncludedPublications(chunk->hypertable_relid);
	foreach (lc, puboids)
	{
		Oid puboid = lfirst_oid(lc);
		chunk_add_to_publication(puboid, chunk);
	}
}

static Chunk *
chunk_create_from_hypercube_after_lock(const Hypertable *ht, Hypercube *cube,
									   const char *schema_name, const char *table_name)
{
	chunk_insert_check_hook_type osm_chunk_insert_hook = ts_get_osm_chunk_insert_hook();

	if (osm_chunk_insert_hook)
	{
		/* OSM only uses first dimension. */
		Dimension *dim = &ht->space->dimensions[0];
		/* convert to PG timestamp from timescaledb internal format */
		int64 range_start =
			ts_internal_to_time_int64(cube->slices[0]->fd.range_start, dim->fd.column_type);
		int64 range_end =
			ts_internal_to_time_int64(cube->slices[0]->fd.range_end, dim->fd.column_type);

		int chunk_exists = osm_chunk_insert_hook(ht->main_table_relid, range_start, range_end);

		if (chunk_exists)
		{
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("Cannot insert into tiered chunk range of %s.%s - attempt to create "
							"new chunk "
							"with range  [%s %s] failed",
							NameStr(ht->fd.schema_name),
							NameStr(ht->fd.table_name),
							ts_internal_to_time_string(cube->slices[0]->fd.range_start,
													   dim->fd.column_type),
							ts_internal_to_time_string(cube->slices[0]->fd.range_end,
													   dim->fd.column_type)),
					 errhint(
						 "Hypertable has tiered data with time range that overlaps the insert")));
		}
	}
	int32 chunk_id = get_next_chunk_id();

	Chunk *chunk = chunk_create_only_table_after_lock(ht, cube, schema_name, table_name, chunk_id);

	ts_chunk_insert_lock(chunk, RowExclusiveLock);
	prepare_cube_slices_for_chunk(cube, chunk_id);
	ts_dimension_slice_insert_multi(cube->slices, cube->num_slices);

	/* Insert any new chunk column stats entries into the catalog */
	ts_chunk_column_stats_insert(ht, chunk);

	chunk_create_table_constraints(ht, chunk);

	/* Add chunk to publications if hypertable is in any publications */
	if (ts_guc_enable_chunk_auto_publication)
	{
		chunk_add_to_publications(chunk);
	}

	return chunk;
}

/*
 * A chunk should have all columns and constraints inherited and none marked as
 * local, so clear the attislocal/conislocal flags that ALTER TABLE ... INHERIT
 * leaves set when attaching a pre-existing table. Otherwise a later DROP COLUMN
 * or DROP CONSTRAINT on the hypertable would not propagate to the chunk.
 * Locally-defined objects (inhcount == 0), such as the chunk's dimension
 * constraints, are left untouched.
 */
static void
chunk_reset_inherited_flags(Oid chunk_relid)
{
	/* Columns */
	Relation attrel = table_open(AttributeRelationId, RowExclusiveLock);
	Relation chunkrel = table_open(chunk_relid, AccessShareLock);
	TupleDesc tupdesc = RelationGetDescr(chunkrel);

	for (int i = 0; i < tupdesc->natts; i++)
	{
		Form_pg_attribute att = TupleDescAttr(tupdesc, i);

		if (att->attisdropped || !att->attislocal || att->attinhcount == 0)
		{
			continue;
		}

		HeapTuple tuple = SearchSysCacheCopyAttNum(chunk_relid, att->attnum);
		if (!HeapTupleIsValid(tuple))
		{
			elog(ERROR,
				 "cache lookup failed for attribute %d of relation %u",
				 att->attnum,
				 chunk_relid);
		}

		((Form_pg_attribute) GETSTRUCT(tuple))->attislocal = false;
		CatalogTupleUpdate(attrel, &tuple->t_self, tuple);
		heap_freetuple(tuple);
	}

	table_close(chunkrel, NoLock);
	table_close(attrel, RowExclusiveLock);

	/* Constraints (CHECK and NOT NULL) */
	ScanKeyData skey;
	ScanKeyInit(&skey,
				Anum_pg_constraint_conrelid,
				BTEqualStrategyNumber,
				F_OIDEQ,
				ObjectIdGetDatum(chunk_relid));

	Relation conrel = table_open(ConstraintRelationId, RowExclusiveLock);
	SysScanDesc scan =
		systable_beginscan(conrel, ConstraintRelidTypidNameIndexId, true, NULL, 1, &skey);
	HeapTuple contup;

	while (HeapTupleIsValid(contup = systable_getnext(scan)))
	{
		Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(contup);

		if (con->coninhcount == 0 || !con->conislocal)
		{
			continue;
		}

		HeapTuple newtup = heap_copytuple(contup);
		((Form_pg_constraint) GETSTRUCT(newtup))->conislocal = false;
		CatalogTupleUpdate(conrel, &newtup->t_self, newtup);
		heap_freetuple(newtup);
	}

	systable_endscan(scan);
	table_close(conrel, RowExclusiveLock);
}

/*
 * Make a chunk table inherit a hypertable.
 *
 * Execution happens via high-level ALTER TABLE statement. This includes
 * numerous checks to ensure that the chunk table has all the prerequisites to
 * properly inherit the hypertable.
 */
static void
chunk_add_inheritance(Chunk *chunk, const Hypertable *ht)
{
	AlterTableCmd altercmd = {
		.type = T_AlterTableCmd,
		.subtype = AT_AddInherit,
		.def = (Node *) makeRangeVar((char *) NameStr(ht->fd.schema_name),
									 (char *) NameStr(ht->fd.table_name),
									 0),
		.missing_ok = false,
	};
	AlterTableStmt alterstmt = {
		.type = T_AlterTableStmt,
		.cmds = list_make1(&altercmd),
		.missing_ok = false,
		.objtype = OBJECT_TABLE,
		.relation = makeRangeVar((char *) ts_chunk_get_schema_name(chunk),
								 (char *) ts_chunk_get_table_name(chunk),
								 0),
	};
	LOCKMODE lockmode = AlterTableGetLockLevel(alterstmt.cmds);
	AlterTableUtilityContext atcontext = {
		.relid = AlterTableLookupRelation(&alterstmt, lockmode),
	};

	AlterTable(&alterstmt, lockmode, &atcontext);

	chunk_reset_inherited_flags(atcontext.relid);
}

static Chunk *
chunk_create_from_hypercube_and_table_after_lock(const Hypertable *ht, Hypercube *cube,
												 Oid chunk_table_relid, const char *schema_name,
												 const char *table_name)
{
	Oid current_chunk_schemaid = get_rel_namespace(chunk_table_relid);
	Oid new_chunk_schemaid = InvalidOid;
	Chunk *chunk;

	Assert(OidIsValid(chunk_table_relid));
	Assert(OidIsValid(current_chunk_schemaid));
	Assert(OidIsValid(ht->main_table_relid));

	Relation ht_rel = table_open(ht->main_table_relid, AccessShareLock);
	Relation chunk_rel = table_open(chunk_table_relid, AccessShareLock);
	TupleDesc tupdesc = RelationGetDescr(chunk_rel);

	for (int attno = 0; attno < tupdesc->natts; attno++)
	{
		Form_pg_attribute att = TupleDescAttr(tupdesc, attno);
		AttrNumber ht_attnum = InvalidAttrNumber;

		/* Ignore dropped */
		if (att->attisdropped)
		{
			continue;
		}

		ht_attnum = get_attnum(ht->main_table_relid, NameStr(att->attname));
		/* Try to find the column in parent (matching on column name) */
		if (ht_attnum == InvalidAttrNumber)
		{
			ereport(ERROR,
					(errcode(ERRCODE_DATATYPE_MISMATCH),
					 errmsg("table \"%s\" contains column \"%s\" not found in parent \"%s\"",
							RelationGetRelationName(chunk_rel),
							NameStr(att->attname),
							RelationGetRelationName(ht_rel)),
					 errdetail("The new chunk can contain only the columns present in parent.")));
		}

		/* Check that the chunk column has the same expression as the hypertable column */
		if (att->attgenerated && get_attgenerated(ht->main_table_relid, ht_attnum))
		{
			char *chunk_expr = ts_get_attr_expr(chunk_rel, attno + 1);
			char *ht_expr = ts_get_attr_expr(ht_rel, ht_attnum);

			if (strcmp(chunk_expr, ht_expr) != 0)
			{
				ereport(ERROR,
						(errcode(ERRCODE_DATATYPE_MISMATCH),
						 errmsg("chunk column \"%s\" must have the same expression as the "
								"hypertable column.",
								NameStr(att->attname))));
			}
		}
	}
	table_close(ht_rel, NoLock);

	int32 chunk_id = get_next_chunk_id();

	if (!schema_name || schema_name[0] == '\0')
	{
		schema_name = NameStr(ht->fd.associated_schema_name);
	}

	chunk = chunk_create_object(ht, cube, chunk_id);
	char *chunk_table_name = chunk_choose_table_name(ht, chunk_id, table_name);
	chunk->fd.relid = chunk_table_relid;

	new_chunk_schemaid = get_namespace_oid(schema_name, false);

	if (current_chunk_schemaid != new_chunk_schemaid)
	{
		ObjectAddresses *objects;

		CheckSetNamespace(current_chunk_schemaid, new_chunk_schemaid);
		objects = new_object_addresses();
		AlterTableNamespaceInternal(chunk_rel, current_chunk_schemaid, new_chunk_schemaid, objects);
		free_object_addresses(objects);
		/* Make changes visible */
		CommandCounterIncrement();
	}
	table_close(chunk_rel, NoLock);

	if (strcmp(chunk_table_name, get_rel_name(chunk_table_relid)) != 0)
	{
		/* Renaming will acquire and keep an AccessExclusivelock on the chunk
		 * table */
		RenameRelationInternal(chunk_table_relid, chunk_table_name, true, false);
		/* Make changes visible */
		CommandCounterIncrement();
	}

	/* Note that we do not automatically add constrains and triggers to the
	 * chunk table when the chunk is created from an existing table. However,
	 * PostgreSQL currently validates that CHECK constraints exists, but no
	 * validation is done for other objects, including triggers, UNIQUE,
	 * PRIMARY KEY, and FOREIGN KEY constraints. We might want to either
	 * enforce that these constraints exist prior to creating the chunk from a
	 * table, or we ensure that they are automatically added when the chunk is
	 * created. However, for the latter case, we risk duplicating constraints
	 * and triggers if some of them already exist on the chunk table prior to
	 * creating the chunk from it. */
	ts_chunk_constraint_check_violated(chunk, ht->space);

	ts_chunk_insert_lock(chunk, RowExclusiveLock);
	prepare_cube_slices_for_chunk(cube, chunk_id);
	ts_dimension_slice_insert_multi(cube->slices, cube->num_slices);

	chunk_add_inheritance(chunk, ht);
	chunk_create_table_constraints(ht, chunk);

	/* Add chunk to publications if hypertable is in any publications */
	if (ts_guc_enable_chunk_auto_publication)
	{
		chunk_add_to_publications(chunk);
	}

	return chunk;
}

static Chunk *
chunk_create_from_point_after_lock(const Hypertable *ht, const Point *p)
{
	Hyperspace *hs = ht->space;
	Hypercube *cube;
	ScanTupLock tuplock = {
		.lockmode = LockTupleKeyShare,
		.waitpolicy = LockWaitBlock,
	};

	/* Calculate the hypercube for a new chunk that covers the tuple's point. */
	cube = ts_hypercube_calculate_from_point(hs, p, &tuplock);

	/* Resolve collisions with other chunks by cutting the new hypercube */
	chunk_collision_resolve(ht, cube, p);

	return chunk_create_from_hypercube_after_lock(ht, cube, NULL, NULL);
}

Chunk *
ts_chunk_find_or_create_without_cuts(const Hypertable *ht, Hypercube *hc, const char *schema_name,
									 const char *table_name, Oid chunk_table_relid, bool *created)
{
	ChunkStub *stub;
	Chunk *chunk = NULL;

	DEBUG_WAITPOINT("find_or_create_chunk_start");

	stub = chunk_collides(ht, hc);

	if (NULL == stub)
	{
		/* Serialize chunk creation around the root hypertable */
		LockRelationOid(ht->main_table_relid, ShareUpdateExclusiveLock);

		/* Check again after lock */
		stub = chunk_collides(ht, hc);

		if (NULL == stub)
		{
			if (OidIsValid(chunk_table_relid))
			{
				chunk = chunk_create_from_hypercube_and_table_after_lock(ht,
																		 hc,
																		 chunk_table_relid,
																		 schema_name,
																		 table_name);
			}
			else
			{
				chunk = chunk_create_from_hypercube_after_lock(ht, hc, schema_name, table_name);
			}

			if (NULL != created)
			{
				*created = true;
			}

			ASSERT_IS_VALID_CHUNK(chunk);

			DEBUG_WAITPOINT("find_or_create_chunk_created");

			return chunk;
		}

		/* We didn't need the lock, so release it */
		UnlockRelationOid(ht->main_table_relid, ShareUpdateExclusiveLock);
	}

	Assert(NULL != stub);

	/* We can only use an existing chunk if it has identical dimensional
	 * constraints. Otherwise, throw an error */
	if (OidIsValid(chunk_table_relid) || !ts_hypercube_equal(stub->cube, hc))
	{
		ereport(ERROR,
				(errcode(ERRCODE_TS_CHUNK_COLLISION),
				 errmsg("chunk creation failed due to collision")));
	}

	/* chunk_collides only returned a stub, so we need to lookup the full
	 * chunk. */
	chunk = ts_chunk_get_by_id(stub->id, true);

	if (NULL != created)
	{
		*created = false;
	}

	DEBUG_WAITPOINT("find_or_create_chunk_found");

	ASSERT_IS_VALID_CHUNK(chunk);

	return chunk;
}

/*
 * Find the chunk containing the given point, locking all its dimension slices
 * for share. NULL if not found.
 */
Chunk *
ts_chunk_find_for_point(const Hypertable *ht, const Point *p, LOCKMODE lockmode)
{
	ScanTupLock slice_lock = {
		.lockmode = LockTupleKeyShare,
		.waitpolicy = LockWaitBlock,
		.lockflags = TUPLE_LOCK_FLAG_FIND_LAST_VERSION,
	};

	int32 chunk_id = ts_chunk_point_find_chunk_id(ht, p, NULL);

	if (chunk_id == INVALID_CHUNK_ID)
	{
		return NULL;
	}

	/* The chunk might be dropped, so we don't fail if we haven't found it. */
	return ts_chunk_get_by_id_with_slice_lock(chunk_id,
											  lockmode,
											  lockmode == NoLock ? NULL : &slice_lock,
											  /* fail_if_not_found = */ false);
}

/*
 * Create a chunk through insertion of a tuple at a given point.
 *
 * If some other process managed to create the chunk before us, the existing
 * chunk is locked with "chunk_lockmode".
 */
Chunk *
ts_chunk_create_for_point(const Hypertable *ht, const Point *p, LOCKMODE chunk_lockmode)
{
	/*
	 * Serialize chunk creation around a lock on the "main table" to avoid
	 * multiple processes trying to create the same chunk. We use a
	 * ShareUpdateExclusiveLock, which is the weakest lock possible that
	 * conflicts with itself. The lock needs to be held until transaction end.
	 */
	LockRelationOid(ht->main_table_relid, ShareUpdateExclusiveLock);

	DEBUG_WAITPOINT("chunk_create_for_point");

	/*
	 * Recheck if someone else created the chunk before we got the table
	 * lock. The returned chunk will have all slices locked so that they
	 * aren't removed.
	 */
	int chunk_id = ts_chunk_point_find_chunk_id(ht, p, NULL);
	if (chunk_id != INVALID_CHUNK_ID)
	{
		ScanTupLock slice_lock = {
			.lockmode = LockTupleKeyShare,
			.waitpolicy = LockWaitBlock,
			.lockflags = TUPLE_LOCK_FLAG_FIND_LAST_VERSION,
		};

		/* The chunk might be dropped, so we don't fail if we haven't found it. */
		Chunk *chunk = ts_chunk_get_by_id_with_slice_lock(chunk_id,
														  chunk_lockmode,
														  &slice_lock,
														  /* fail_if_not_found = */ false);
		if (chunk != NULL)
		{
			/*
			 * Chunk was not created by us but by someone else, so we can
			 * release the lock early.
			 */
			UnlockRelationOid(ht->main_table_relid, ShareUpdateExclusiveLock);
			return chunk;
		}
	}

	/* Create the chunk normally. */
	Chunk *chunk = chunk_create_from_point_after_lock(ht, p);

	ASSERT_IS_VALID_CHUNK(chunk);

	return chunk;
}

static void
scan_add_chunk_context(ChunkScanCtx *ctx, int32 chunk_id, List *dimension_vecs, List **l_chunk_ids)
{
	bool found = false;
	ChunkScanEntry *entry = hash_search(ctx->htab, &chunk_id, HASH_ENTER, &found);
	if (!found)
	{
		entry->stub = NULL;
		entry->num_dimension_constraints = 0;
	}

	entry->num_dimension_constraints++;

	/*
	 * A chunk is complete when we've found slices for all required dimensions,
	 * i.e., a complete subspace.
	 */
	if (entry->num_dimension_constraints == list_length(dimension_vecs))
	{
		*l_chunk_ids = lappend_int(*l_chunk_ids, entry->chunk_id);
	}
}

/*
 * Find the chunks that belong to the subspace identified by the given dimension
 * vectors. We might be restricting only some dimensions, so this subspace is
 * not a hypercube, but a hyperplane of some order.
 * Returns a list of matching chunk ids.
 */
List *
ts_chunk_id_find_in_subspace(Hypertable *ht, List *dimension_vecs)
{
	List *chunk_ids = NIL;

	ChunkScanCtx ctx;
	chunk_scan_ctx_init(&ctx, ht, /* point = */ NULL);

	ListCell *lc;
	foreach (lc, dimension_vecs)
	{
		const DimensionVec *vec = lfirst(lc);

		/*
		 * If it's an entry of type DIMENSION_TYPE_STATS then we need to get
		 * the chunks using the _timescaledb_catalog.chunk_column_stats catalog.
		 */
		Assert(vec->dri != NULL);
		if (vec->dri->dimension->type == DIMENSION_TYPE_STATS)
		{
			ListCell *lc;
			List *range_chunk_ids;

			Assert(vec->num_slices == 0);
			range_chunk_ids = ts_chunk_column_stats_get_chunk_ids_by_scan(vec->dri);

			/* add these chunks to the context appropriately. */
			foreach (lc, range_chunk_ids)
			{
				int32 chunk_id = lfirst_int(lc);

				scan_add_chunk_context(&ctx, chunk_id, dimension_vecs, &chunk_ids);
			}
			continue;
		}

		/*
		 * We shouldn't see a dimension with zero matching dimension slices.
		 * That would mean that no chunks match at all, this should have been
		 * handled earlier by gather_restriction_dimension_vectors().
		 */
		Assert(vec->num_slices > 0);
		for (int i = 0; i < vec->num_slices; i++)
		{
			const DimensionSlice *slice = vec->slices[i];
			int32 current_chunk_id = slice->fd.chunk_id;

			Assert(current_chunk_id != INVALID_CHUNK_ID);
			scan_add_chunk_context(&ctx, current_chunk_id, dimension_vecs, &chunk_ids);
		}
	}

	chunk_scan_ctx_destroy(&ctx);

	return chunk_ids;
}

ChunkStub *
ts_chunk_stub_create(int32 id)
{
	ChunkStub *stub = palloc0(sizeof(*stub));

	stub->id = id;

	return stub;
}

Chunk *
ts_chunk_create_base(int32 id)
{
	Chunk *chunk = palloc0(sizeof(Chunk));

	chunk->fd.id = id;
	chunk->relkind = RELKIND_RELATION;
	chunk->fd.creation_time = GetCurrentTimestamp();

	return chunk;
}

/*
 * Build a chunk from a chunk tuple.
 *
 * The dimension slices are scanned from the catalog to build the chunk's cube.
 */
Chunk *
ts_chunk_build_from_tuple(Chunk **chunkptr, TupleInfo *ti)
{
	Chunk *chunk = NULL;

	if (chunkptr == NULL)
	{
		chunkptr = &chunk;
	}

	if (*chunkptr == NULL)
	{
		*chunkptr = MemoryContextAllocZero(ti->mctx, sizeof(Chunk));
	}

	chunk = *chunkptr;
	ts_chunk_formdata_fill(&chunk->fd, ti);

	/* Build the cube directly from dimension_slice rows owned by this chunk. */
	{
		List *slices = ts_dimension_slice_scan_by_chunk_id(chunk->fd.id, ti->mctx);
		ListCell *lc;
		MemoryContext oldctx = MemoryContextSwitchTo(ti->mctx);

		chunk->cube = ts_hypercube_alloc(list_length(slices));
		MemoryContextSwitchTo(oldctx);
		foreach (lc, slices)
		{
			chunk->cube->slices[chunk->cube->num_slices++] = (DimensionSlice *) lfirst(lc);
		}
		ts_hypercube_slice_sort(chunk->cube);
	}

	chunk->hypertable_relid = ts_hypertable_id_to_relid(chunk->fd.hypertable_id, false);
	chunk->relkind = get_rel_relkind(chunk->fd.relid);

	Ensure(chunk->relkind > 0,
		   "relkind for chunk \"%s\".\"%s\" is invalid",
		   ts_chunk_get_schema_name(chunk),
		   ts_chunk_get_table_name(chunk));

	return chunk;
}

static ScanTupleResult
chunk_tuple_found(TupleInfo *ti, void *arg)
{
	ChunkStubScanCtx *stubctx = arg;

	/*
	 * The chunk table could also have been dropped concurrently. Try to
	 * acquire the requested lock in order to guarantee that the chunk table
	 * still exists.
	 */
	if (stubctx->chunk_lockmode != NoLock)
	{
		bool isnull;
		Oid relid = DatumGetObjectId(slot_getattr(ti->slot, Anum_chunk_relid, &isnull));
		Assert(!isnull);

		if (!ts_chunk_lock_if_exists(relid, stubctx->chunk_lockmode))
		{
			return SCAN_DONE;
		}
	}

	ts_chunk_build_from_tuple(&stubctx->chunk, ti);

	return SCAN_DONE;
}

/* Create a chunk by scanning on chunk ID. A stub must be provided as input. */
static Chunk *
chunk_create_from_stub(ChunkStubScanCtx *stubctx)
{
	ScanKeyData scankey[1];
	Catalog *catalog = ts_catalog_get();
	int num_found;
	ScannerCtx scanctx = {
		.table = catalog_get_table_id(catalog, CHUNK),
		.index = catalog_get_index(catalog, CHUNK, CHUNK_ID_INDEX),
		.nkeys = 1,
		.scankey = scankey,
		.data = stubctx,
		.tuple_found = chunk_tuple_found,
		.lockmode = AccessShareLock,
		.scandirection = ForwardScanDirection,
	};

	/*
	 * Perform an index scan on chunk ID.
	 */
	ScanKeyInit(&scankey[0],
				Anum_chunk_idx_id,
				BTEqualStrategyNumber,
				F_INT4EQ,
				Int32GetDatum(stubctx->stub->id));

	num_found = ts_scanner_scan(&scanctx);

	Assert(num_found == 0 || num_found == 1);

	if (num_found != 1)
	{
		elog(ERROR, "no chunk found with ID %d", stubctx->stub->id);
	}

	Assert(stubctx->chunk != NULL);

	return stubctx->chunk;
}

/*
 * Initialize a chunk scan context.
 *
 * A chunk scan context is used to join chunk-related information from metadata
 * tables during scans.
 */
static void
chunk_scan_ctx_init(ChunkScanCtx *ctx, const Hypertable *ht, const Point *point)
{
	struct HASHCTL hctl = {
		.keysize = sizeof(int32),
		.entrysize = sizeof(ChunkScanEntry),
		.hcxt = CurrentMemoryContext,
	};

	memset(ctx, 0, sizeof(*ctx));
	ctx->htab = hash_create("chunk-scan-context", 20, &hctl, HASH_ELEM | HASH_CONTEXT | HASH_BLOBS);
	ctx->ht = ht;
	ctx->point = point;
	ctx->lockmode = NoLock;
}

/*
 * Destroy the chunk scan context.
 *
 * This will free the hash table in the context, but not the chunks within since
 * they are not allocated on the hash tables memory context.
 */
static void
chunk_scan_ctx_destroy(ChunkScanCtx *ctx)
{
	hash_destroy(ctx->htab);
}

static inline void
dimension_slice_join_chunks(ChunkScanCtx *scanctx, const DimensionVec *vec)
{
	const Hyperspace *hs = scanctx->ht->space;

	for (int i = 0; i < vec->num_slices; i++)
	{
		DimensionSlice *slice = vec->slices[i];
		int32 chunk_id = slice->fd.chunk_id;
		bool found;
		ChunkScanEntry *entry = hash_search(scanctx->htab, &chunk_id, HASH_ENTER, &found);
		ChunkStub *stub;

		if (!found)
		{
			stub = ts_chunk_stub_create(chunk_id);
			stub->cube = ts_hypercube_alloc(hs->num_dimensions);
			entry->stub = stub;
		}
		else
		{
			stub = entry->stub;
		}

		ts_hypercube_add_slice(stub->cube, slice);

		if (chunk_stub_is_complete(stub, hs))
		{
			scanctx->num_complete_chunks++;

			if (scanctx->early_abort)
			{
				break;
			}
		}
	}
}

/*
 * Scan for chunks that collide with the given hypercube.
 *
 * Collisions are determined using axis-aligned bounding box collision detection
 * generalized to N dimensions. Slices are collected in the scan context's hash
 * table according to the chunk IDs they are associated with. A slice might
 * represent the dimensional bound of multiple chunks, and thus is added to all
 * the hash table slots of those chunks. At the end of the scan, those chunks
 * that have a full set of slices are the ones that actually collide with the
 * given hypercube.
 *
 * Chunks in the scan context that do not collide (do not have a full set of
 * slices), might still be important for ensuring alignment in those dimensions
 * that require alignment.
 */
static void
chunk_collision_scan(ChunkScanCtx *scanctx, const Hypercube *cube)
{
	int i;

	/* Scan all dimensions for colliding slices */
	for (i = 0; i < scanctx->ht->space->num_dimensions; i++)
	{
		DimensionVec *vec;
		DimensionSlice *slice = cube->slices[i];

		vec = dimension_slice_collision_scan(slice->fd.dimension_id,
											 slice->fd.range_start,
											 slice->fd.range_end);

		/* Add the slices to all the chunks they are associated with */
		dimension_slice_join_chunks(scanctx, vec);
	}
}

/*
 * Apply a function to each stub in the scan context's hash table. If the limit
 * is greater than zero only a limited number of chunks will be processed.
 *
 * The chunk handler function (on_chunk_func) should return CHUNK_PROCESSED if
 * the chunk should be considered processed and count towards the given
 * limit. CHUNK_IGNORE can be returned to have a chunk NOT count towards the
 * limit. CHUNK_DONE counts the chunk but aborts processing irrespective of
 * whether the limit is reached or not.
 *
 * Returns the number of processed chunks.
 */
static int
chunk_scan_ctx_foreach_chunk_stub(ChunkScanCtx *ctx, on_chunk_stub_func on_chunk, uint64 limit)
{
	HASH_SEQ_STATUS status;
	ChunkScanEntry *entry;

	ctx->num_processed = 0;
	hash_seq_init(&status, ctx->htab);

	for (entry = hash_seq_search(&status); entry != NULL; entry = hash_seq_search(&status))
	{
		switch (on_chunk(ctx, entry->stub))
		{
			case CHUNK_DONE:
				ctx->num_processed++;
				hash_seq_term(&status);
				return ctx->num_processed;
			case CHUNK_PROCESSED:
				ctx->num_processed++;

				if (limit > 0 && ctx->num_processed == limit)
				{
					hash_seq_term(&status);
					return ctx->num_processed;
				}
				break;
			case CHUNK_IGNORED:
				break;
		}
	}

	return ctx->num_processed;
}

typedef struct ChunkScanCtxAddChunkData
{
	Chunk *chunks;
	uint64 max_chunks;
	uint64 num_chunks;
} ChunkScanCtxAddChunkData;

static ChunkResult
chunk_scan_context_add_chunk(ChunkScanCtx *scanctx, ChunkStub *stub)
{
	ChunkScanCtxAddChunkData *data = scanctx->data;
	ChunkStubScanCtx stubctx = {
		.chunk = &data->chunks[data->num_chunks],
		.stub = stub,
	};

	Assert(data->num_chunks < data->max_chunks);
	chunk_create_from_stub(&stubctx);

	data->num_chunks++;

	return CHUNK_PROCESSED;
}

TM_Result
ts_chunk_lock_for_creating_compressed_chunk(Chunk *chunk)
{
	ScanIterator iterator;
	bool found = false;
	TM_Result lockresult;
	ScanTupLock tuplock = {
		.lockmode = LockTupleExclusive,
		.waitpolicy = LockWaitBlock,
		.lockflags = TUPLE_LOCK_FLAG_FIND_LAST_VERSION,
	};

	iterator = ts_scan_iterator_create(CHUNK, RowShareLock, CurrentMemoryContext);
	ts_chunk_scan_iterator_set_chunk_id(&iterator, chunk->fd.id);
	iterator.ctx.tuplock = &tuplock;

	ts_scanner_foreach(&iterator)
	{
		TupleInfo *ti = ts_scan_iterator_tuple_info(&iterator);
		lockresult = ti->lockresult;

		/*
		 * Refresh the chunk's status from the locked tuple so the caller can
		 * recheck whether the chunk was compressed concurrently.
		 */
		if (lockresult == TM_Ok)
		{
			bool isnull;
			Datum value = slot_getattr(ti->slot, Anum_chunk_status, &isnull);
			Assert(!isnull);
			chunk->fd.status = DatumGetInt32(value);
		}
		found = true;
	}

	ts_scan_iterator_close(&iterator);

	if (!found)
	{
		elog(ERROR, "chunk with ID %d does not exist", chunk->fd.id);
	}

	return lockresult;
}

/*
 * Scan for the chunk that encloses the given point.
 *
 * In each dimension there can be one or more slices that match the point's
 * coordinate in that dimension. Slices are collected in the scan context's hash
 * table according to the chunk IDs they are associated with. A slice might
 * represent the dimensional bound of multiple chunks, and thus is added to all
 * the hash table slots of those chunks. At the end of the scan there will be at
 * most one chunk that has a complete set of slices, since a point cannot belong
 * to two chunks.
 *
 * This involves:
 *
 * 1) For each dimension:
 *	  - Find all dimension slices that match the dimension and read off the
 *	    owning chunk_id from each slice row.
 * 2) Tally how many dimensions each chunk matched. The chunk that matched
 *	  every dimension is the chunk containing the point.
 *
 * NOTE: this function allocates transient data, e.g., dimension slice,
 * constraints and chunks, that in the end are not part of the returned
 * chunk. Therefore, this scan should be executed on a transient memory
 * context. The returned chunk needs to be copied into another memory context in
 * case it needs to live beyond the lifetime of the other data.
 *
 * The slices can be locked by specifying an optional slice lock.
 */
int32
ts_chunk_point_find_chunk_id(const Hypertable *ht, const Point *p, const ScanTupLock *slice_lock)
{
	int32 matching_chunk_id = 0;

	/* The scan context will keep the state accumulated during the scan */
	ChunkScanCtx ctx;
	chunk_scan_ctx_init(&ctx, ht, p);

	/* Scan all dimensions for slices enclosing the point */
	List *all_slices = NIL;
	for (int dimension_index = 0; dimension_index < ctx.ht->space->num_dimensions;
		 dimension_index++)
	{
		ts_dimension_slice_scan_list(ctx.ht->space->dimensions[dimension_index].fd.id,
									 p->coordinates[dimension_index],
									 &all_slices,
									 slice_lock);
	}

	ListCell *lc;
	foreach (lc, all_slices)
	{
		DimensionSlice *slice = (DimensionSlice *) lfirst(lc);
		int32 current_chunk_id = slice->fd.chunk_id;
		Assert(current_chunk_id != INVALID_CHUNK_ID);

		bool found = false;
		ChunkScanEntry *entry = hash_search(ctx.htab, &current_chunk_id, HASH_ENTER, &found);
		if (!found)
		{
			entry->stub = NULL;
			entry->num_dimension_constraints = 0;
		}

		entry->num_dimension_constraints++;

		/*
		 * A chunk is complete when we've matched a slice in every dimension.
		 * Only one chunk can match a given point so we can stop early.
		 */
		if (entry->num_dimension_constraints == ctx.ht->space->num_dimensions)
		{
			matching_chunk_id = entry->chunk_id;
			break;
		}
	}

	chunk_scan_ctx_destroy(&ctx);

	return matching_chunk_id;
}

/*
 * Find all the chunks in hyperspace that include elements (dimension slices)
 * calculated by given range constraints and return the corresponding
 * ChunkScanCxt. It is the caller's responsibility to destroy this context after
 * usage.
 */
static void
chunks_find_all_in_range_limit(const Hypertable *ht, const Dimension *time_dim,
							   StrategyNumber start_strategy, int64 start_value,
							   StrategyNumber end_strategy, int64 end_value, int limit,
							   uint64 *num_found, ScanTupLock *tuplock, ChunkScanCtx *ctx)
{
	DimensionVec *slices;

	Assert(ht != NULL);

	/* must have been checked earlier that this is the case */
	Assert(time_dim != NULL);

	slices = ts_dimension_slice_scan_range_limit(time_dim->fd.id,
												 start_strategy,
												 start_value,
												 end_strategy,
												 end_value,
												 limit,
												 tuplock);

	/* The scan context will keep the state accumulated during the scan */
	chunk_scan_ctx_init(ctx, ht, NULL);

	/* No abort when the first chunk is found */
	ctx->early_abort = false;

	/* Scan for chunks that are in range */
	dimension_slice_join_chunks(ctx, slices);

	*num_found += hash_get_num_entries(ctx->htab);
}

/* show_chunks SQL function handler */
Datum
ts_chunk_show_chunks(PG_FUNCTION_ARGS)
{
	/*
	 * show_chunks_return_srf is called even when it is not the first call but only
	 * after doing some computation first
	 */
	if (SRF_IS_FIRSTCALL())
	{
		FuncCallContext *funcctx;
		Oid relid = PG_ARGISNULL(0) ? InvalidOid : PG_GETARG_OID(0);
		Hypertable *ht;
		const Dimension *time_dim;
		Cache *hcache;
		int64 older_than = PG_INT64_MAX;
		int64 newer_than = PG_INT64_MIN;
		int64 created_before = PG_INT64_MAX;
		int64 created_after = PG_INT64_MIN;
		Oid time_type;
		Oid arg_type;
		bool older_newer = false;
		bool before_after = false;

		hcache = ts_hypertable_cache_pin();
		ht = ts_resolve_hypertable_from_table_or_cagg(hcache, relid, true);
		Assert(ht != NULL);
		time_dim = hyperspace_get_open_dimension(ht->space, 0);

		if (!time_dim)
		{
			time_dim = hyperspace_get_closed_dimension(ht->space, 0);
		}

		if (time_dim && IS_CLOSED_DIMENSION(time_dim) && (!PG_ARGISNULL(1) || !PG_ARGISNULL(2)))
		{
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("cannot specify \"older_than\" or \"newer_than\" for "
							"\"closed\"-like partitioning types"),
					 errhint("Use \"created_before\" and/or \"created_after\" which rely on the "
							 "chunk creation time values.")));
		}

		if (time_dim)
		{
			time_type = ts_dimension_get_partition_type(time_dim);
		}
		else
		{
			time_type = InvalidOid;
		}

		/*
		 * Treat UUID (v7) as a timestamptz type. The expected input is an interval or absolute
		 * timestamptz.
		 */
		if (IS_UUID_TYPE(time_type))
		{
			time_type = TIMESTAMPTZOID;
		}

		/* note that arg_types will be the same for all specified "ANY" elements for a given call */
		arg_type = InvalidOid;
		if (!PG_ARGISNULL(1))
		{
			arg_type = get_fn_expr_argtype(fcinfo->flinfo, 1);
			older_than = ts_time_value_from_arg(PG_GETARG_DATUM(1), arg_type, time_type, true);
			older_newer = true;
		}

		if (!PG_ARGISNULL(2))
		{
			arg_type = get_fn_expr_argtype(fcinfo->flinfo, 2);
			newer_than = ts_time_value_from_arg(PG_GETARG_DATUM(2), arg_type, time_type, true);
			older_newer = true;
		}

		/*
		 * We cannot have a mix of [older_than/newer_than] and [created_before/created_after].
		 * So, check that first. Note that created_before/created_after have a type of
		 * TIMESTAMPTZOID regardless of the partitioning type.
		 */

		if (!PG_ARGISNULL(3))
		{
			if (older_newer)
			{
				ereport(ERROR,
						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
						 errmsg("cannot specify \"older_than\" or \"newer_than\" together with "
								"\"created_before\""
								"or \"created_after\"")));
			}

			arg_type = get_fn_expr_argtype(fcinfo->flinfo, 3);
			/* We use the existing function for various type/conversion checks */
			created_before =
				ts_time_value_from_arg(PG_GETARG_DATUM(3), arg_type, TIMESTAMPTZOID, false);
			/* convert into int64 format for comparisons */
			created_before = ts_internal_to_time_int64(created_before, TIMESTAMPTZOID);
			before_after = true;
		}

		if (!PG_ARGISNULL(4))
		{
			if (older_newer)
			{
				ereport(ERROR,
						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
						 errmsg("cannot specify \"older_than\" or \"newer_than\" together with "
								"\"created_before\""
								"or \"created_after\"")));
			}

			arg_type = get_fn_expr_argtype(fcinfo->flinfo, 4);
			/* We use the existing function for various type/conversion checks */
			created_after =
				ts_time_value_from_arg(PG_GETARG_DATUM(4), arg_type, TIMESTAMPTZOID, false);
			/* convert into int64 format for comparisons */
			created_after = ts_internal_to_time_int64(created_after, TIMESTAMPTZOID);
			before_after = true;
		}

		/* if both have not been specified then default to older_newer */
		if (!older_newer && !before_after)
		{
			older_newer = true;
		}

		funcctx = SRF_FIRSTCALL_INIT();
		/*
		 * For INTEGER type dimensions, we support querying using intervals or any
		 * timestamp or date input. For such INTEGER dimensions, we get the chunks
		 * using their creation time values.
		 */
		if (IS_INTEGER_TYPE(time_type) && (arg_type == INTERVALOID || IS_TIMESTAMP_TYPE(arg_type)))
		{
			/* check that we use proper inputs for such cases */
			if (older_newer)
			{
				ereport(ERROR,
						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
						 errmsg("cannot specify \"older_than\" and/or \"newer_than\" for "
								"\"integer\"-like partitioning types"),
						 errhint(
							 "Use \"created_before\" and/or \"created_after\" which rely on the "
							 "chunk creation time values.")));
			}
			funcctx->user_fctx = get_chunks_in_creation_time_range(ht,
																   created_before,
																   created_after,
																   funcctx->multi_call_memory_ctx,
																   &funcctx->max_calls,
																   NULL);
		}
		else
		{
			/* check that we use proper inputs for such cases */
			if (!older_newer)
			{
				funcctx->user_fctx =
					get_chunks_in_creation_time_range(ht,
													  created_before,
													  created_after,
													  funcctx->multi_call_memory_ctx,
													  &funcctx->max_calls,
													  NULL);
			}
			else
			{
				funcctx->user_fctx = get_chunks_in_time_range(ht,
															  older_than,
															  newer_than,
															  funcctx->multi_call_memory_ctx,
															  &funcctx->max_calls,
															  NULL);
			}
		}
		ts_cache_release(&hcache);
	}

	return show_chunks_return_srf(fcinfo);
}

static Chunk *
get_chunks_in_time_range(Hypertable *ht, int64 older_than, int64 newer_than, MemoryContext mctx,
						 uint64 *num_chunks_returned, ScanTupLock *tuplock)
{
	MemoryContext oldcontext;
	ChunkScanCtx chunk_scan_ctx;
	Chunk *chunks;
	ChunkScanCtxAddChunkData data;
	const Dimension *time_dim;
	StrategyNumber start_strategy;
	StrategyNumber end_strategy;
	uint64 num_chunks = 0;

	if (older_than <= newer_than)
	{
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				 errmsg("invalid time range"),
				 errhint("The start of the time range must be before the end.")));
	}

	start_strategy = (newer_than == PG_INT64_MIN) ? InvalidStrategy : BTGreaterEqualStrategyNumber;
	end_strategy = (older_than == PG_INT64_MAX) ? InvalidStrategy : BTLessStrategyNumber;
	time_dim = hyperspace_get_open_dimension(ht->space, 0);

	if (time_dim == NULL)
	{
		time_dim = hyperspace_get_closed_dimension(ht->space, 0);
	}

	Ensure(time_dim != NULL,
		   "partitioning dimension not found for hypertable \"%s\".\"%s\"",
		   NameStr(ht->fd.schema_name),
		   NameStr(ht->fd.table_name));

	oldcontext = MemoryContextSwitchTo(mctx);
	chunks_find_all_in_range_limit(ht,
								   time_dim,
								   start_strategy,
								   newer_than,
								   end_strategy,
								   older_than,
								   -1,
								   &num_chunks,
								   tuplock,
								   &chunk_scan_ctx);
	MemoryContextSwitchTo(oldcontext);

	chunks = MemoryContextAllocZero(mctx, sizeof(Chunk) * num_chunks);
	data = (ChunkScanCtxAddChunkData){
		.chunks = chunks,
		.max_chunks = num_chunks,
		.num_chunks = 0,
	};

	/* Get all the chunks from the context */
	chunk_scan_ctx.data = &data;
	chunk_scan_ctx_foreach_chunk_stub(&chunk_scan_ctx, chunk_scan_context_add_chunk, 0);
	/*
	 * only affects ctx.htab Got all the chunk already so can now safely
	 * destroy the context
	 */
	chunk_scan_ctx_destroy(&chunk_scan_ctx);

	*num_chunks_returned = data.num_chunks;
	qsort(chunks, *num_chunks_returned, sizeof(Chunk), chunk_cmp);

#ifdef USE_ASSERT_CHECKING
	do
	{
		uint64 i = 0;
		/* Assert that we never return dropped chunks */
		for (i = 0; i < *num_chunks_returned; i++)
		{
			ASSERT_IS_VALID_CHUNK(&chunks[i]);
		}
	} while (false);
#endif

	return chunks;
}

Chunk *
ts_chunk_copy(const Chunk *chunk)
{
	Chunk *copy;

	ASSERT_IS_VALID_CHUNK(chunk);
	copy = palloc(sizeof(Chunk));
	memcpy(copy, chunk, sizeof(Chunk));

	if (NULL != chunk->cube)
	{
		copy->cube = ts_hypercube_copy(chunk->cube);
	}

	return copy;
}

static int
chunk_scan_internal(int indexid, ScanKeyData scankey[], int nkeys, tuple_found_func tuple_found,
					void *data, int limit, ScanDirection scandir, LOCKMODE lockmode,
					MemoryContext mctx)
{
	Catalog *catalog = ts_catalog_get();
	ScannerCtx ctx = {
		.table = catalog_get_table_id(catalog, CHUNK),
		.index = catalog_get_index(catalog, CHUNK, indexid),
		.nkeys = nkeys,
		.data = data,
		.scankey = scankey,
		.tuple_found = tuple_found,
		.limit = limit,
		.lockmode = lockmode,
		.scandirection = scandir,
		.result_mctx = mctx,
	};

	return ts_scanner_scan(&ctx);
}

static Chunk *
chunk_scan_find(int indexid, ScanKeyData scankey[], int nkeys, MemoryContext mctx,
				LOCKMODE chunk_lockmode, const ScanTupLock *slice_lock, bool fail_if_not_found,
				const DisplayKeyData displaykey[])
{
	ChunkStubScanCtx stubctx = {
		.slice_lock = slice_lock,
		.chunk_lockmode = chunk_lockmode,
	};
	Chunk *chunk;
	int num_found;

	num_found = chunk_scan_internal(indexid,
									scankey,
									nkeys,
									chunk_tuple_found,
									&stubctx,
									1,
									ForwardScanDirection,
									AccessShareLock,
									mctx);

	Assert(num_found == 0 || num_found == 1);
	chunk = stubctx.chunk;

	switch (num_found)
	{
		case 0:
			if (fail_if_not_found)
			{
				int i = 0;
				StringInfoData info;
				initStringInfo(&info);
				while (i < nkeys)
				{
					appendStringInfo(&info,
									 "%s: %s",
									 displaykey[i].name,
									 displaykey[i].as_string(scankey[i].sk_argument));
					if (++i < nkeys)
					{
						appendStringInfoString(&info, ", ");
					}
				}
				ereport(ERROR,
						(errcode(ERRCODE_UNDEFINED_OBJECT),
						 errmsg("chunk not found"),
						 errdetail("%s", info.data)));
			}
			break;
		case 1:
			if (chunk)
			{
				ASSERT_IS_VALID_CHUNK(chunk);
			}
			break;
		default:
			elog(ERROR, "expected a single chunk, found %d", num_found);
	}

	return chunk;
}

Chunk *
ts_chunk_get_by_name_with_memory_context(const char *schema_name, const char *table_name,
										 LOCKMODE chunk_lockmode, const ScanTupLock *slice_lock,
										 MemoryContext mctx, bool fail_if_not_found)
{
	Oid relid;
	Chunk *chunk;
	MemoryContext oldctx;

	/* Early check for rogue input */
	if (schema_name == NULL || table_name == NULL)
	{
		if (fail_if_not_found)
		{
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_OBJECT),
					 errmsg("chunk not found"),
					 errdetail("schema_name: %s, table_name: %s",
							   schema_name ? schema_name : "<null>",
							   table_name ? table_name : "<null>")));
		}
		else
		{
			return NULL;
		}
	}

	relid = ts_get_relation_relid(schema_name, table_name, /* return_invalid = */ true);

	if (!OidIsValid(relid))
	{
		if (fail_if_not_found)
		{
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_OBJECT),
					 errmsg("chunk not found"),
					 errdetail("schema_name: %s, table_name: %s", schema_name, table_name)));
		}
		return NULL;
	}

	/* The chunk is identified by its relation; look it up by relid. */
	oldctx = MemoryContextSwitchTo(mctx);
	chunk = ts_chunk_get_by_relid_locked(relid, chunk_lockmode, slice_lock, fail_if_not_found);
	MemoryContextSwitchTo(oldctx);

	return chunk;
}

Chunk *
ts_chunk_get_by_relid_locked(Oid relid, LOCKMODE chunk_lockmode, const ScanTupLock *slice_lock,
							 bool fail_if_not_found)
{
	ScanKeyData scankey[1];
	static const DisplayKeyData displaykey[1] = {
		[0] = { .name = "relid", .as_string = DatumGetRegClassString },
	};

	if (!OidIsValid(relid))
	{
		if (fail_if_not_found)
		{
			ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("invalid Oid")));
		}
		else
		{
			return NULL;
		}
	}

	/*
	 * Check that the relation actually exists and get a lock, unless no lock
	 * requested. If it was dropped the catalog row is gone too and the scan
	 * below finds nothing.
	 */
	if (chunk_lockmode != NoLock && !ts_chunk_lock_if_exists(relid, chunk_lockmode))
	{
		if (fail_if_not_found)
		{
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_OBJECT),
					 errmsg("chunk not found"),
					 errdetail("relid: %u", relid)));
		}
		return NULL;
	}

	ScanKeyInit(&scankey[0],
				Anum_chunk_relid_idx_relid,
				BTEqualStrategyNumber,
				F_OIDEQ,
				ObjectIdGetDatum(relid));

	return chunk_scan_find(CHUNK_RELID_INDEX,
						   scankey,
						   1,
						   CurrentMemoryContext,
						   chunk_lockmode,
						   slice_lock,
						   fail_if_not_found,
						   displaykey);
}

Chunk *
ts_chunk_get_by_relid(Oid relid, bool fail_if_not_found)
{
	ScanTupLock slice_lock = {
		.lockmode = LockTupleKeyShare,
		.waitpolicy = LockWaitBlock,
		.lockflags = TUPLE_LOCK_FLAG_FIND_LAST_VERSION,
	};
	return ts_chunk_get_by_relid_locked(relid, NoLock, &slice_lock, fail_if_not_found);
}

void
ts_chunk_free(Chunk *chunk)
{
	if (chunk->cube)
	{
		ts_hypercube_free(chunk->cube);
	}

	pfree(chunk);
}

static const char *
DatumGetInt32AsString(Datum datum)
{
	char *buf = (char *) palloc(12); /* sign, 10 digits, '\0' */
	pg_ltoa(DatumGetInt32(datum), buf);
	return buf;
}

Chunk *
ts_chunk_get_by_id_with_slice_lock(int32 id, LOCKMODE chunk_lockmode, const ScanTupLock *slice_lock,
								   bool fail_if_not_found)
{
	ScanKeyData scankey[1];
	static const DisplayKeyData displaykey[1] = {
		[0] = { .name = "id", .as_string = DatumGetInt32AsString },
	};

	/*
	 * Perform an index scan on chunk id.
	 */
	ScanKeyInit(&scankey[0], Anum_chunk_idx_id, BTEqualStrategyNumber, F_INT4EQ, Int32GetDatum(id));

	return chunk_scan_find(CHUNK_ID_INDEX,
						   scankey,
						   1,
						   CurrentMemoryContext,
						   chunk_lockmode,
						   slice_lock,
						   fail_if_not_found,
						   displaykey);
}

Chunk *
ts_chunk_get_by_id(int32 id, bool fail_if_not_found)
{
	ScanTupLock slice_lock = {
		.lockmode = LockTupleKeyShare,
		.waitpolicy = LockWaitBlock,
		.lockflags = TUPLE_LOCK_FLAG_FIND_LAST_VERSION,
	};

	return ts_chunk_get_by_id_with_slice_lock(id, NoLock, &slice_lock, fail_if_not_found);
}

/*
 * Simple scans provide lightweight ways to access chunk information without the
 * overhead of getting a full chunk (i.e., no extra metadata, like constraints,
 * are joined in). This function forms the basis of a number of lookup functions
 * that, e.g., translates a chunk relid to a chunk_id, or vice versa.
 */
static bool
chunk_simple_scan(ScanIterator *iterator, FormData_chunk *form, bool missing_ok,
				  const DisplayKeyData displaykey[])
{
	int count = 0;

	ts_scanner_foreach(iterator)
	{
		TupleInfo *ti = ts_scan_iterator_tuple_info(iterator);
		ts_chunk_formdata_fill(form, ti);
		count++;
	}

	Assert(count == 0 || count == 1);

	if (count == 0 && !missing_ok)
	{
		int i = 0;
		StringInfoData info;
		initStringInfo(&info);
		while (i < iterator->ctx.nkeys)
		{
			appendStringInfo(&info,
							 "%s: %s",
							 displaykey[i].name,
							 displaykey[i].as_string(iterator->ctx.scankey[i].sk_argument));
			if (++i < iterator->ctx.nkeys)
			{
				appendStringInfoString(&info, ", ");
			}
		}
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("chunk not found"),
				 errdetail("%s", info.data)));
	}

	return count == 1;
}

static bool
chunk_simple_scan_by_relid(Oid relid, FormData_chunk *form, bool missing_ok)
{
	ScanIterator iterator;
	static const DisplayKeyData displaykey[] = {
		[0] = { .name = "relid", .as_string = DatumGetRegClassString },
	};

	if (!OidIsValid(relid))
	{
		return false;
	}

	iterator = ts_scan_iterator_create(CHUNK, AccessShareLock, CurrentMemoryContext);
	init_scan_by_relid(&iterator, relid);

	return chunk_simple_scan(&iterator, form, missing_ok, displaykey);
}

static bool
chunk_simple_scan_by_name(const char *schema, const char *table, FormData_chunk *form,
						  bool missing_ok)
{
	if (schema == NULL || table == NULL)
	{
		return false;
	}

	return chunk_simple_scan_by_relid(ts_get_relation_relid(schema, table, true), form, missing_ok);
}

bool
ts_chunk_simple_scan_by_reloid(Oid reloid, FormData_chunk *form, bool missing_ok)
{
	bool found = chunk_simple_scan_by_relid(reloid, form, missing_ok);

	if (!found && !missing_ok)
	{
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("chunk with reloid %u not found", reloid)));
	}

	return found;
}

static bool
chunk_simple_scan_by_id(int32 chunk_id, FormData_chunk *form, bool missing_ok)
{
	ScanIterator iterator;
	static const DisplayKeyData displaykey[] = {
		[0] = { .name = "id", .as_string = DatumGetInt32AsString },
	};

	iterator = ts_scan_iterator_create(CHUNK, AccessShareLock, CurrentMemoryContext);
	ts_chunk_scan_iterator_set_chunk_id(&iterator, chunk_id);

	return chunk_simple_scan(&iterator, form, missing_ok, displaykey);
}

/*
 * Lookup a Chunk ID from a chunk's relid.
 */
Datum
ts_chunk_id_from_relid(PG_FUNCTION_ARGS)
{
	static Oid last_relid = InvalidOid;
	static int32 last_id = 0;
	Oid relid = PG_GETARG_OID(0);
	FormData_chunk form;

	if (last_relid == relid)
	{
		return last_id;
	}

	ts_chunk_simple_scan_by_reloid(relid, &form, false);

	last_relid = relid;
	last_id = form.id;

	PG_RETURN_INT32(last_id);
}

bool
ts_chunk_exists_relid(Oid relid)
{
	FormData_chunk form;

	return ts_chunk_simple_scan_by_reloid(relid, &form, true);
}

/*
 * Returns 0 if there is no chunk with such reloid.
 */
int32
ts_chunk_get_hypertable_id_by_reloid(Oid reloid)
{
	FormData_chunk form;

	if (ts_chunk_simple_scan_by_reloid(reloid, &form, /* missing_ok = */ true))
	{
		return form.hypertable_id;
	}

	return 0;
}

FormData_chunk
ts_chunk_get_formdata(int32 chunk_id)
{
	FormData_chunk fd;
	chunk_simple_scan_by_id(chunk_id, &fd, /* missing_ok = */ false);
	return fd;
}

/*
 * Get the relid of a chunk given its ID.
 */
Oid
ts_chunk_get_relid(int32 chunk_id, bool missing_ok)
{
	FormData_chunk form = { 0 };
	Oid relid = InvalidOid;

	if (chunk_simple_scan_by_id(chunk_id, &form, missing_ok))
	{
		relid = form.relid;
	}

	if (!OidIsValid(relid) && !missing_ok)
	{
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_SCHEMA),
				 errmsg("chunk with id %d not found", chunk_id)));
	}

	return relid;
}

/*
 * Get the schema (namespace) of a chunk given its ID.
 *
 * This is a lightweight way to get the schema of a chunk without creating a
 * full Chunk object that joins in constraints, etc.
 */
Oid
ts_chunk_get_schema_id(int32 chunk_id, bool missing_ok)
{
	FormData_chunk form = { 0 };

	if (!chunk_simple_scan_by_id(chunk_id, &form, missing_ok))
	{
		return InvalidOid;
	}

	return get_rel_namespace(form.relid);
}

bool
ts_chunk_get_id(const char *schema, const char *table, int32 *chunk_id, bool missing_ok)
{
	FormData_chunk form = { 0 };

	if (!chunk_simple_scan_by_name(schema, table, &form, missing_ok))
	{
		return false;
	}

	if (NULL != chunk_id)
	{
		*chunk_id = form.id;
	}

	return true;
}

/* Delete the chunk tuple.
 *
 * relid: Required when deleting via an event trigger hook, because at that
 * point the relation is gone and it is no longer possible to resolve the Oid
 * from the PG catalog.
 *
 */
static void
chunk_tuple_delete(TupleInfo *ti, Oid relid, DropBehavior behavior, bool detach)
{
	FormData_chunk form;
	CatalogSecurityContext sec_ctx;

	/*
	 * chunk_delete locked this chunk row for us. Check the lock result before
	 * touching the tuple: in read committed mode the lock followed any
	 * concurrent update to the latest version, so the only remaining conflict
	 * is a chunk that was deleted by another transaction.
	 */
	switch (ti->lockresult)
	{
		case TM_Ok:
		case TM_SelfModified:
			break;
		case TM_Deleted:
		case TM_Updated:
		case TM_BeingModified:
			if (IsolationUsesXactSnapshot())
			{
				ereport(ERROR,
						(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
						 errmsg("could not serialize access due to concurrent update")));
			}
			ereport(ERROR,
					(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
					 errmsg("chunk %s by other transaction",
							ti->lockresult == TM_Deleted ? "deleted" : "updated"),
					 errhint("Retry the operation again.")));
			break;
		default:
			elog(ERROR, "unexpected chunk tuple lock result %d", ti->lockresult);
			break;
	}

	ts_chunk_formdata_fill(&form, ti);

	/*
	 * Delete the chunk's dimension slices.
	 * When detaching, the relation stays around, so drop the dimensional CHECKs too.
	 * When the relation itself is being dropped Postgres takes care of that.
	 */
	List *chunk_slices = ts_dimension_slice_scan_by_chunk_id(form.id, CurrentMemoryContext);
	ListCell *lc;

	foreach (lc, chunk_slices)
	{
		DimensionSlice *slice = (DimensionSlice *) lfirst(lc);

		/*
		 * TODO: We should adjust this in the future to leave CHECK
		 * constraints in place when detaching and try to pick up existing
		 * constraints when reattaching.
		 */
		if (detach && OidIsValid(relid))
		{
			char check_name[NAMEDATALEN];
			Oid check_oid;

			snprintf(check_name, NAMEDATALEN, "constraint_%d", slice->fd.id);
			check_oid = get_relation_constraint_oid(relid, check_name, true);
			if (OidIsValid(check_oid))
			{
				ObjectAddress addr = {
					.classId = ConstraintRelationId,
					.objectId = check_oid,
				};
				performDeletion(&addr, DROP_RESTRICT, 0);
			}
		}

		ts_dimension_slice_delete_by_id(slice->fd.id);
	}

	/*
	 * Drop FKs that reference this chunk. They target the chunk's PK index
	 * directly, so without explicit removal the index would block the chunk
	 * drop. Skip when the relation is already gone (cascade from hypertable).
	 */
	if (detach && OidIsValid(relid) && SearchSysCacheExists1(RELOID, ObjectIdGetDatum(relid)))
	{
		ts_chunk_drop_referencing_fk_by_chunk_id(form.id);
	}
	ts_compression_chunk_size_delete(form.id);

	/* Delete any row in bgw_policy_chunk-stats corresponding to this chunk */
	ts_bgw_policy_chunk_stats_delete_by_chunk_id(form.id);

	/* Delete any rows in _timescaledb_catalog.chunk_column_stats corresponding to this chunk */
	ts_chunk_column_stats_delete_by_chunk_id(form.id);

	if (!OidIsValid(relid))
	{
		/*
		 * If the chunk is deleted as a result of deleting the Hypertable, and
		 * it is cleaned up in the DROP eventtrigger hook, it might not be
		 * possible to resolve the relid because the relation is already gone
		 * in pg_catalog. But that's OK, because compression settings will be
		 * cleaned up when processing the eventtrigger.
		 */
		if (OidIsValid(form.relid) && SearchSysCacheExists1(RELOID, ObjectIdGetDatum(form.relid)))
		{
			relid = form.relid;
		}
	}

	/*
	 * Cleanup dependent catalogs.
	 */
	if (OidIsValid(relid))
	{
		ts_chunk_rewrite_delete(relid, false);
	}

	if (ts_flags_are_set_32(DatumGetInt32(form.status), CHUNK_STATUS_COMPRESSED))
	{
		Oid compressed_relid = ts_relation_get_compressed_relid(relid);

		if (OidIsValid(relid))
		{
			ts_compression_settings_delete(relid);
		}

		/* The compressed relation's oid is recorded in the compression
		 * settings, but the relation itself may already have been dropped by a
		 * CASCADE. Only drop it if it still exists; get_rel_name() returns NULL
		 * once the relation is gone. */
		if (OidIsValid(compressed_relid) && get_rel_name(compressed_relid) != NULL)
		{
			/* Plain drop without preserving catalog row because this is the compressed
			 * chunk */
			ts_chunk_drop_by_relid(compressed_relid, behavior, DEBUG1);
		}
	}
	else if (OidIsValid(relid))
	{
		/* If there is no compressed chunk ID, this might be the actual
		 * compressed chunk */
		ts_compression_settings_delete_by_compress_relid(relid);
	}

	ts_catalog_database_info_become_owner(ts_catalog_database_info_get(), &sec_ctx);
	ts_catalog_delete_tid(ti->scanrel, ts_scanner_get_tuple_tid(ti));
	ts_catalog_restore_user(&sec_ctx);
}

static void
init_scan_by_relid(ScanIterator *iterator, Oid relid)
{
	iterator->ctx.index = catalog_get_index(ts_catalog_get(), CHUNK, CHUNK_RELID_INDEX);
	ts_scan_iterator_scan_key_init(iterator,
								   Anum_chunk_relid_idx_relid,
								   BTEqualStrategyNumber,
								   F_OIDEQ,
								   ObjectIdGetDatum(relid));
}

static int
chunk_delete(ScanIterator *iterator, Oid relid, DropBehavior behavior, bool detach)
{
	int count = 0;
	ScanTupLock tuplock = {
		.waitpolicy = LockWaitBlock,
		.lockmode = LockTupleExclusive,
		.lockflags = TUPLE_LOCK_FLAG_LOCK_UPDATE_IN_PROGRESS,
	};

	/*
	 * Lock each chunk row before deleting it. In read committed mode we follow
	 * the update chain to the latest version, so a concurrent compress_chunk
	 * (which updates the chunk row) does not turn the catalog delete into a raw
	 * "tuple concurrently updated" error. A concurrent delete is reported
	 * cleanly in chunk_tuple_delete instead.
	 */
	if (!IsolationUsesXactSnapshot())
	{
		tuplock.lockflags |= TUPLE_LOCK_FLAG_FIND_LAST_VERSION;
	}
	iterator->ctx.tuplock = &tuplock;

	ts_scanner_foreach(iterator)
	{
		chunk_tuple_delete(ts_scan_iterator_tuple_info(iterator), relid, behavior, detach);
		count++;
	}

	return count;
}

static int
ts_chunk_delete_by_relid_internal(Oid relid, DropBehavior behavior)
{
	ScanIterator iterator = ts_scan_iterator_create(CHUNK, RowExclusiveLock, CurrentMemoryContext);
	int count;

	init_scan_by_relid(&iterator, relid);
	count = chunk_delete(&iterator, relid, behavior, false);

	/* relid is unique so should only have dropped one chunk or none (if not found) */
	Assert(count == 1 || count == 0);

	return count;
}

int
ts_chunk_delete_by_name(const char *schema, const char *table, DropBehavior behavior)
{
	Oid relid = ts_get_relation_relid(schema, table, false);
	return ts_chunk_delete_by_relid_internal(relid, behavior);
}

int
ts_chunk_delete_by_relid(Oid relid, DropBehavior behavior)
{
	if (!OidIsValid(relid))
	{
		return 0;
	}

	return ts_chunk_delete_by_relid_internal(relid, behavior);
}

static void
init_scan_by_hypertable_id(ScanIterator *iterator, int32 hypertable_id)
{
	iterator->ctx.index = catalog_get_index(ts_catalog_get(), CHUNK, CHUNK_HYPERTABLE_ID_INDEX);
	ts_scan_iterator_scan_key_init(iterator,
								   Anum_chunk_hypertable_id_idx_hypertable_id,
								   BTEqualStrategyNumber,
								   F_INT4EQ,
								   Int32GetDatum(hypertable_id));
}

int
ts_chunk_delete_by_hypertable_id(int32 hypertable_id)
{
	ScanIterator iterator = ts_scan_iterator_create(CHUNK, RowExclusiveLock, CurrentMemoryContext);

	init_scan_by_hypertable_id(&iterator, hypertable_id);

	return chunk_delete(&iterator, InvalidOid, DROP_RESTRICT, false);
}

bool
ts_chunk_exists_with_compression(int32 hypertable_id)
{
	ScanIterator iterator = ts_scan_iterator_create(CHUNK, AccessShareLock, CurrentMemoryContext);
	bool found = false;

	init_scan_by_hypertable_id(&iterator, hypertable_id);
	ts_scanner_foreach(&iterator)
	{
		bool status_isnull;
		Datum status =
			slot_getattr(ts_scan_iterator_slot(&iterator), Anum_chunk_status, &status_isnull);

		if (!status_isnull && ts_flags_are_set_32(DatumGetInt32(status), CHUNK_STATUS_COMPRESSED))
		{
			found = true;
			break;
		}
	}
	ts_scan_iterator_close(&iterator);
	return found;
}

List *
ts_chunk_get_chunk_ids_by_hypertable_id(int32 hypertable_id)
{
	List *chunkids = NIL;
	ScanIterator iterator = ts_scan_iterator_create(CHUNK, AccessShareLock, CurrentMemoryContext);

	init_scan_by_hypertable_id(&iterator, hypertable_id);
	ts_scanner_foreach(&iterator)
	{
		bool isnull;
		Datum id = slot_getattr(ts_scan_iterator_slot(&iterator), Anum_chunk_id, &isnull);
		if (!isnull)
		{
			chunkids = lappend_int(chunkids, DatumGetInt32(id));
		}
	}

	return chunkids;
}

/* Return list of chunks that belong to the given hypertable.
 *
 * The returned chunk objects will not have any constraints or dimension
 * information filled in.
 */
List *
ts_chunk_get_by_hypertable_id(int32 hypertable_id)
{
	List *chunks = NIL;
	Oid hypertable_relid = ts_hypertable_id_to_relid(hypertable_id, false);

	ScanIterator iterator = ts_scan_iterator_create(CHUNK, RowExclusiveLock, CurrentMemoryContext);

	init_scan_by_hypertable_id(&iterator, hypertable_id);
	ts_scanner_foreach(&iterator)
	{
		TupleInfo *ti = ts_scan_iterator_tuple_info(&iterator);
		Chunk *chunk = palloc0(sizeof(Chunk));
		ts_chunk_formdata_fill(&chunk->fd, ti);

		chunk->hypertable_relid = hypertable_relid;

		chunks = lappend(chunks, chunk);
	}

	return chunks;
}

static ChunkResult
chunk_recreate_constraint(ChunkScanCtx *ctx, ChunkStub *stub)
{
	ChunkStubScanCtx stubctx = {
		.stub = stub,
	};
	Chunk *chunk = chunk_create_from_stub(&stubctx);

	ts_chunk_constraints_recreate(ctx->ht, chunk);

	return CHUNK_PROCESSED;
}

void
ts_chunk_recreate_all_constraints_for_dimension(Hypertable *ht, int32 dimension_id)
{
	DimensionVec *slices;
	ChunkScanCtx chunkctx;

	slices = ts_dimension_slice_scan_by_dimension(dimension_id, 0);

	if (NULL == slices)
	{
		return;
	}

	chunk_scan_ctx_init(&chunkctx, ht, NULL);

	dimension_slice_join_chunks(&chunkctx, slices);

	chunk_scan_ctx_foreach_chunk_stub(&chunkctx, chunk_recreate_constraint, 0);
	chunk_scan_ctx_destroy(&chunkctx);
}

/*
 * Chunk catalog updates are done in three steps.
 * This is achieved by following this sequence:
 *   1: call lock_chunk_tuple: this finds most recent version of tuple,
 *   locks it, fills TID and data
 *   2: make changes to the data
 *   3: call chunk_update_catalog_tuple with the TID and updated data
 *
 * This is equivalent to SELECT for UPDATE, followed by UPDATE
 *
 * All callers who want to update chunk tuples should respect this so that locks
 * are acquired correctly.
 *
 */
static void
chunk_update_catalog_tuple(ItemPointer tid, FormData_chunk *update)
{
	HeapTuple new_tuple;
	CatalogSecurityContext sec_ctx;
	Catalog *catalog = ts_catalog_get();
	Oid table = catalog_get_table_id(catalog, CHUNK);
	Relation chunk_rel = relation_open(table, RowExclusiveLock);

	new_tuple = chunk_formdata_make_tuple(update, chunk_rel->rd_att);

	ts_catalog_database_info_become_owner(ts_catalog_database_info_get(), &sec_ctx);
	ts_catalog_update_tid(chunk_rel, tid, new_tuple);
	ts_catalog_restore_user(&sec_ctx);
	heap_freetuple(new_tuple);
	relation_close(chunk_rel, NoLock);
}
/*
 * This function locks the  timescaledb_catalog.chunk tuple (corresponding to chunk_id ) in
 * LockTupleExclusiveMode. It blocks till the lock is acquired. The tid and data (corresponding to
 * the locked tuple) are returned via tid and form arguments. Anyone updating/deleting a chunk entry
 * from the catalog table is expected to first call this function. Refer to
 * chunk_update_catalog_tuple() for more details.
 */
static bool
lock_chunk_tuple(int32 chunk_id, ItemPointer tid, FormData_chunk *form)
{
	ScanTupLock scantuplock = {
		.waitpolicy = LockWaitBlock,
		.lockmode = LockTupleExclusive,
	};
	ScanIterator iterator = ts_scan_iterator_create(CHUNK, RowShareLock, CurrentMemoryContext);
	iterator.ctx.index = catalog_get_index(ts_catalog_get(), CHUNK, CHUNK_ID_INDEX);
	iterator.ctx.tuplock = &scantuplock;
	/* Keeping the lock since we presumably want to update the tuple */
	iterator.ctx.flags = SCANNER_F_KEEPLOCK;

	/* see table_tuple_lock for details about flags that are set in TupleExclusive mode */
	scantuplock.lockflags = TUPLE_LOCK_FLAG_LOCK_UPDATE_IN_PROGRESS;
	if (!IsolationUsesXactSnapshot())
	{
		/* in read committed mode, we follow all updates to this tuple */
		scantuplock.lockflags |= TUPLE_LOCK_FLAG_FIND_LAST_VERSION;
	}

	ts_scan_iterator_scan_key_init(&iterator,
								   Anum_chunk_idx_id,
								   BTEqualStrategyNumber,
								   F_INT4EQ,
								   Int32GetDatum(chunk_id));
	bool success = false;

	ts_scanner_foreach(&iterator)
	{
		TupleInfo *ti = ts_scan_iterator_tuple_info(&iterator);

		if (ti->lockresult != TM_Ok)
		{
			if (IsolationUsesXactSnapshot())
			{
				/* For Repeatable Read and Serializable isolation level report error
				 * if we cannot lock the tuple
				 */
				ereport(ERROR,
						(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
						 errmsg("could not serialize access due to concurrent update")));
			}
			else
			{
				ereport(ERROR,
						(errcode(ERRCODE_INTERNAL_ERROR),
						 errmsg("unable to lock chunk catalog tuple, lock result is %d for chunk "
								"ID (%d)",
								ti->lockresult,
								chunk_id)));
			}
		}

		ts_chunk_formdata_fill(form, ti);
		ItemPointer result_tid = ts_scanner_get_tuple_tid(ti);
		tid->ip_blkid = result_tid->ip_blkid;
		tid->ip_posid = result_tid->ip_posid;
		success = true;
		break;
	}
	ts_scan_iterator_close(&iterator);

	return success;
}

/*
 * Lock a chunk catalog row before dropping the chunk.
 */
static void
lock_chunk_for_drop(int32 chunk_id)
{
	ScanTupLock scantuplock = {
		.waitpolicy = LockWaitBlock,
		.lockmode = LockTupleExclusive,
		.lockflags = TUPLE_LOCK_FLAG_LOCK_UPDATE_IN_PROGRESS,
	};
	ScanIterator iterator = ts_scan_iterator_create(CHUNK, RowShareLock, CurrentMemoryContext);
	iterator.ctx.index = catalog_get_index(ts_catalog_get(), CHUNK, CHUNK_ID_INDEX);
	iterator.ctx.tuplock = &scantuplock;

	if (!IsolationUsesXactSnapshot())
	{
		scantuplock.lockflags |= TUPLE_LOCK_FLAG_FIND_LAST_VERSION;
	}

	ts_scan_iterator_scan_key_init(&iterator,
								   Anum_chunk_idx_id,
								   BTEqualStrategyNumber,
								   F_INT4EQ,
								   Int32GetDatum(chunk_id));

	ts_scanner_foreach(&iterator)
	{
		TupleInfo *ti = ts_scan_iterator_tuple_info(&iterator);

		if (ti->lockresult != TM_Ok && ti->lockresult != TM_SelfModified)
		{
			if (IsolationUsesXactSnapshot())
			{
				ereport(ERROR,
						(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
						 errmsg("could not serialize access due to concurrent update")));
			}
			ereport(ERROR,
					(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
					 errmsg("chunk %s by other transaction",
							ti->lockresult == TM_Deleted ? "deleted" : "updated")));
		}
	}
	ts_scan_iterator_close(&iterator);
}

bool
ts_chunk_set_unordered(Chunk *chunk)
{
	Assert(ts_chunk_is_compressed(chunk));
	return ts_chunk_add_status(chunk, CHUNK_STATUS_COMPRESSED_UNORDERED);
}

bool
ts_chunk_set_partial(Chunk *chunk)
{
	bool set_status;

	Assert(ts_chunk_is_compressed(chunk));
	set_status = ts_chunk_add_status(chunk, CHUNK_STATUS_COMPRESSED_PARTIAL);

	if (set_status)
	{
		/*
		 * If the status was set then convert the corresponding
		 * _timescaledb_catalog.chunk_column_stats entries "INVALID".
		 */
		ts_chunk_column_stats_set_invalid(chunk->fd.hypertable_id, chunk->fd.id);

		/* changed chunk status, so invalidate plans involving this chunk */
		CacheInvalidateRelcacheByRelid(chunk->fd.relid);
	}
	return set_status;
}

/* No inserts, updates, and deletes are permitted on a frozen chunk.
 * Compression policies etc do not run on a frozen chunk.
 * Only valid operation is dropping the chunk
 */
bool
ts_chunk_set_frozen(Chunk *chunk)
{
	return ts_chunk_add_status(chunk, CHUNK_STATUS_FROZEN);
}

bool
ts_chunk_unset_frozen(Chunk *chunk)
{
	return ts_chunk_clear_status(chunk, CHUNK_STATUS_FROZEN);
}

bool
ts_chunk_is_frozen(const Chunk *chunk)
{
	return ts_flags_are_set_32(chunk->fd.status, CHUNK_STATUS_FROZEN);
}

/* only caller used to be ts_chunk_unset_frozen. This code was in PG14 block as we run into
 * a "defined but unset" error in CI/CD builds for PG < 14. But now called from recompress as well
 */
bool
ts_chunk_clear_status(Chunk *chunk, int32 status)
{
	/* only frozen status can be cleared for a frozen chunk */
	if (status != CHUNK_STATUS_FROZEN && ts_flags_are_set_32(chunk->fd.status, CHUNK_STATUS_FROZEN))
	{
		/* chunk in frozen state cannot be modified */
		ereport(ERROR,
				(errcode(ERRCODE_TS_OPERATION_NOT_SUPPORTED),
				 errmsg("cannot modify frozen chunk status"),
				 errdetail("chunk id = %d attempt to clear status %d , current status %x ",
						   chunk->fd.id,
						   status,
						   chunk->fd.status)));
	}

	FormData_chunk form;
	ItemPointerData tid;
	bool PG_USED_FOR_ASSERTS_ONLY found;

	found = lock_chunk_tuple(chunk->fd.id, &tid, &form);
	Assert(found);

	/* applying the flags after locking the metadata tuple */
	int32 old_status = form.status;
	form.status = ts_clear_flags_32(form.status, status);
	chunk->fd.status = form.status;

	/* Row-level locks are released at transaction end or during savepoint rollback */
	if (old_status != form.status)
	{
		chunk_update_catalog_tuple(&tid, &form);
	}

	return true;
}

static bool
ts_chunk_add_status(Chunk *chunk, int32 status)
{
	bool status_set = false;
	if (ts_flags_are_set_32(chunk->fd.status, CHUNK_STATUS_FROZEN))
	{
		/* chunk in frozen state cannot be modified */
		ereport(ERROR,
				(errcode(ERRCODE_TS_OPERATION_NOT_SUPPORTED),
				 errmsg("cannot modify frozen chunk status"),
				 errdetail("chunk id = %d attempt to set status %d , current status %x ",
						   chunk->fd.id,
						   status,
						   chunk->fd.status)));
	}
	FormData_chunk form;
	ItemPointerData tid;
	bool PG_USED_FOR_ASSERTS_ONLY found;

	found = lock_chunk_tuple(chunk->fd.id, &tid, &form);
	Assert(found);

	/* Somebody could update the status before we are able to lock it so check again */
	if (ts_flags_are_set_32(form.status, CHUNK_STATUS_FROZEN))
	{
		/* chunk in frozen state cannot be modified */
		ereport(ERROR,
				(errcode(ERRCODE_TS_OPERATION_NOT_SUPPORTED),
				 errmsg("cannot modify frozen chunk status"),
				 errdetail("chunk id = %d attempt to set status %d , current status %d ",
						   chunk->fd.id,
						   status,
						   form.status)));
	}

	/* applying the flags after locking the metadata tuple */
	int32 old_status = form.status;
	form.status = ts_set_flags_32(form.status, status);
	chunk->fd.status = form.status;

	/* Row-level locks are released at transaction end or during savepoint rollback */
	if (old_status != form.status)
	{
		chunk_update_catalog_tuple(&tid, &form);
		status_set = true;
	}

	return status_set;
}

/*Assume permissions are already checked */
bool
ts_chunk_set_compressed(Chunk *chunk)
{
	uint32 flags = CHUNK_STATUS_COMPRESSED;
	uint32 mstatus = ts_set_flags_32(chunk->fd.status, flags);
	if (ts_flags_are_set_32(chunk->fd.status, CHUNK_STATUS_FROZEN))
	{
		/* chunk in frozen state cannot be modified */
		ereport(ERROR,
				(errcode(ERRCODE_TS_OPERATION_NOT_SUPPORTED),
				 errmsg("cannot modify frozen chunk status"),
				 errdetail("chunk id = %d attempt to set status %d , current status %d ",
						   chunk->fd.id,
						   mstatus,
						   chunk->fd.status)));
	}

	FormData_chunk form;
	ItemPointerData tid;
	bool PG_USED_FOR_ASSERTS_ONLY found;

	found = lock_chunk_tuple(chunk->fd.id, &tid, &form);
	Assert(found);

	/* Somebody could update the status before we are able to lock it so check again */
	if (ts_flags_are_set_32(form.status, CHUNK_STATUS_FROZEN))
	{
		/* chunk in frozen state cannot be modified */
		ereport(ERROR,
				(errcode(ERRCODE_TS_OPERATION_NOT_SUPPORTED),
				 errmsg("cannot modify frozen chunk status"),
				 errdetail("chunk id = %d attempt to set status %d , current status %d ",
						   chunk->fd.id,
						   mstatus,
						   form.status)));
	}

	/* re-applying the flags after locking the metadata tuple */
	form.status = ts_set_flags_32(form.status, flags);
	chunk->fd.status = form.status;

	chunk_update_catalog_tuple(&tid, &form);
	return true;
}

/*Assume permissions are already checked */
bool
ts_chunk_clear_compressed(Chunk *chunk)
{
	uint32 flags = CHUNK_STATUS_COMPRESSED | CHUNK_STATUS_COMPRESSED_UNORDERED |
				   CHUNK_STATUS_COMPRESSED_PARTIAL;
	uint32 mstatus = ts_clear_flags_32(chunk->fd.status, flags);
	if (ts_flags_are_set_32(chunk->fd.status, CHUNK_STATUS_FROZEN))
	{
		/* chunk in frozen state cannot be modified */
		ereport(ERROR,
				(errcode(ERRCODE_TS_OPERATION_NOT_SUPPORTED),
				 errmsg("cannot modify frozen chunk status"),
				 errdetail("chunk id = %d attempt to set status %d , current status %d ",
						   chunk->fd.id,
						   mstatus,
						   chunk->fd.status)));
	}

	FormData_chunk form;
	ItemPointerData tid;
	bool PG_USED_FOR_ASSERTS_ONLY found;

	found = lock_chunk_tuple(chunk->fd.id, &tid, &form);
	Assert(found);

	/* Somebody could update the status before we are able to lock it so check again */
	if (ts_flags_are_set_32(form.status, CHUNK_STATUS_FROZEN))
	{
		/* chunk in frozen state cannot be modified */
		ereport(ERROR,
				(errcode(ERRCODE_TS_OPERATION_NOT_SUPPORTED),
				 errmsg("cannot modify frozen chunk status"),
				 errdetail("chunk id = %d attempt to set status %d , current status %d ",
						   chunk->fd.id,
						   mstatus,
						   form.status)));
	}

	/* re-applying the flags after locking the metadata tuple */
	form.status = ts_clear_flags_32(form.status, flags);
	chunk->fd.status = form.status;

	chunk_update_catalog_tuple(&tid, &form);
	return true;
}

static int
chunk_cmp(const void *ch1, const void *ch2)
{
	const Chunk *v1 = ((const Chunk *) ch1);
	const Chunk *v2 = ((const Chunk *) ch2);

	if (v1->fd.hypertable_id < v2->fd.hypertable_id)
	{
		return -1;
	}
	if (v1->fd.hypertable_id > v2->fd.hypertable_id)
	{
		return 1;
	}
	if (v1->fd.relid < v2->fd.relid)
	{
		return -1;
	}
	if (v1->fd.relid > v2->fd.relid)
	{
		return 1;
	}
	return 0;
}

/*
 * This is a helper set returning function (SRF) that takes a set returning function context
 * and as argument and returns oids extracted from funcctx->user_fctx (which is Chunk*
 * array). Note that the caller needs to be registered as a set returning function for this
 * to work.
 */
static Datum
show_chunks_return_srf(FunctionCallInfo fcinfo)
{
	FuncCallContext *funcctx;
	uint64 call_cntr;
	TupleDesc tupdesc;
	Chunk *result_set;
	Chunk *curr_chunk;

	/* stuff done only on the first call of the function */
	if (SRF_IS_FIRSTCALL())
	{
		/* Build a tuple descriptor for our result type */
		/* not quite necessary */
		if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_SCALAR)
		{
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("function returning record called in context "
							"that cannot accept type record")));
		}
	}

	/* stuff done on every call of the function */
	funcctx = SRF_PERCALL_SETUP();

	call_cntr = funcctx->call_cntr;
	result_set = (Chunk *) funcctx->user_fctx;

	/*
	 * skip if it's an OSM chunk. Ideally this check could be done deep down in
	 * functions like "chunk_scan_context_add_chunk", "chunk_tuple_dropped_filter"
	 * etc. but they are used by other APIs like drop_chunks, chunk_scan_find, etc
	 * which need access to the OSM chunk. Trying to unify scan functions across
	 * all such usages seems to be too much of an overhaul as compared to this.
	 *
	 * Check the index appropriately first.
	 */
	if (call_cntr < funcctx->max_calls)
	{
		curr_chunk = &result_set[call_cntr];
		if (IS_OSM_CHUNK(curr_chunk))
		{
			call_cntr = ++funcctx->call_cntr;
		}
	}

	/* do when there is more left to send */
	if (call_cntr < funcctx->max_calls)
	{
		SRF_RETURN_NEXT(funcctx, result_set[call_cntr].fd.relid);
	}
	else /* do when there is no more left */
	{
		SRF_RETURN_DONE(funcctx);
	}
}

void
ts_chunk_drop(const Chunk *chunk, DropBehavior behavior, int32 log_level)
{
	ObjectAddress objaddr = {
		.classId = RelationRelationId,
		.objectId = chunk->fd.relid,
	};

	if (log_level >= 0)
	{
		const char *schema_name = ts_chunk_get_schema_name(chunk);
		const char *table_name = ts_chunk_get_table_name(chunk);

		elog(log_level, "dropping chunk %s.%s", schema_name, table_name);
	}

	/* Remove the chunk from the chunk table */
	ts_chunk_delete_by_relid(chunk->fd.relid, behavior);

	/* Drop the table */
	performDeletion(&objaddr, behavior, 0);

	/* Evict the chunk stats from the shared memory */
	ts_stats_chunk_evict(chunk->fd.relid);
}

void
ts_chunk_drop_by_relid(Oid relid, DropBehavior behavior, int32 log_level)
{
	ObjectAddress objaddr = {
		.classId = RelationRelationId,
		.objectId = relid,
	};

	if (log_level >= 0)
	{
		const char *schema_name = get_namespace_name(get_rel_namespace(relid));
		const char *table_name = get_rel_name(relid);

		elog(log_level, "dropping chunk %s.%s", schema_name, table_name);
	}

	/* Remove the chunk from the chunk table */
	ts_chunk_delete_by_relid(relid, behavior);

	/* Drop the table */
	performDeletion(&objaddr, behavior, 0);

	/* Evict the chunk stats from the shared memory */
	ts_stats_chunk_evict(relid);
}

static void
lock_referenced_tables(Oid table_relid)
{
	List *fk_relids = NIL;
	ListCell *lf;
	List *cachedfkeys = NIL;
	Relation table_rel = table_open(table_relid, AccessShareLock);

	/* this list is from the relcache and can disappear with a cache flush, so
	 * no further catalog access till we save the fk relids */
	cachedfkeys = RelationGetFKeyList(table_rel);
	foreach (lf, cachedfkeys)
	{
		ForeignKeyCacheInfo *cachedfk = lfirst_node(ForeignKeyCacheInfo, lf);

		/* conrelid should always be that of the table we're considering */
		Assert(cachedfk->conrelid == RelationGetRelid(table_rel));
		fk_relids = lappend_oid(fk_relids, cachedfk->confrelid);
	}
	table_close(table_rel, AccessShareLock);
	foreach (lf, fk_relids)
	{
		LockRelationOid(lfirst_oid(lf), AccessExclusiveLock);
	}
}

List *
ts_chunk_do_drop_chunks(Hypertable *ht, int64 older_than, int64 newer_than, int32 log_level,
						Oid time_type, Oid arg_type, bool older_newer)

{
	uint64 num_chunks = 0;
	Chunk *chunks;
	const char *schema_name, *table_name;
	const int32 hypertable_id = ht->fd.id;
	bool has_continuous_aggs, is_materialization_hypertable;
	const MemoryContext oldcontext = CurrentMemoryContext;
	ScanTupLock tuplock = {
		.waitpolicy = LockWaitBlock,
		.lockmode = LockTupleExclusive,
	};

	ts_hypertable_permissions_check(ht->main_table_relid, GetUserId());

	/* We have a FK between hypertable H and PAR. Hypertable H has number of
	 * chunks C1, C2, etc. When we execute "drop table C", PG acquires locks
	 * on C and PAR. If we have a query as "select * from hypertable", this
	 * acquires a lock on C and PAR as well. But the order of the locks is not
	 * the same and results in deadlocks. - github issue #865 We hope to
	 * alleviate the problem by acquiring a lock on PAR before executing the
	 * drop table stmt. This is not fool-proof as we could have multiple
	 * fkrelids and the order of lock acquisition for these could differ as
	 * well. Do not unlock - let the transaction semantics take care of it. */
	lock_referenced_tables(ht->main_table_relid);

	is_materialization_hypertable = false;

	switch (ts_continuous_agg_hypertable_status(hypertable_id))
	{
		case HypertableIsMaterialization:
			has_continuous_aggs = false;
			is_materialization_hypertable = true;
			break;
		case HypertableIsMaterializationAndRaw:
			has_continuous_aggs = true;
			is_materialization_hypertable = true;
			break;
		case HypertableIsRawTable:
			has_continuous_aggs = true;
			break;
		default:
			has_continuous_aggs = false;
			break;
	}

	PG_TRY();
	{
		/*
		 * For INTEGER type dimensions, we support querying using intervals or any
		 * timestamp or date input. For such INTEGER dimensions, we get the chunks
		 * using their creation time values.
		 */
		if (IS_INTEGER_TYPE(time_type) && (arg_type == INTERVALOID || IS_TIMESTAMP_TYPE(arg_type)))
		{
			chunks = get_chunks_in_creation_time_range(ht,
													   older_than,
													   newer_than,
													   CurrentMemoryContext,
													   &num_chunks,
													   &tuplock);
		}
		else
		{
			if (!older_newer)
			{
				chunks = get_chunks_in_creation_time_range(ht,
														   older_than,
														   newer_than,
														   CurrentMemoryContext,
														   &num_chunks,
														   &tuplock);
			}
			else
			{
				chunks = get_chunks_in_time_range(ht,
												  older_than,
												  newer_than,
												  CurrentMemoryContext,
												  &num_chunks,
												  &tuplock);
			}
		}

		for (uint64 i = 0; i < num_chunks; i++)
		{
			lock_chunk_for_drop(chunks[i].fd.id);
		}
	}
	PG_CATCH();
	{
		ErrorData *edata;
		MemoryContextSwitchTo(oldcontext);
		edata = CopyErrorData();
		FlushErrorState();
		if (edata->sqlerrcode == ERRCODE_LOCK_NOT_AVAILABLE)
		{
			edata->detail = edata->message;
			edata->message =
				psprintf("some chunks could not be read since they are being concurrently updated");
		}
		ReThrowError(edata);
	}
	PG_END_TRY();

	DEBUG_WAITPOINT("drop_chunks_chunks_found");

	int32 osm_chunk_id = ts_chunk_get_osm_chunk_id(ht->fd.id);
	if (has_continuous_aggs)
	{
		/* Exclusively lock all chunks, and invalidate the continuous
		 * aggregates in the regions covered by the chunks. We do this in two
		 * steps: first lock all the chunks and then invalidate the
		 * regions. Since we are going to drop the chunks, there is no point
		 * in allowing inserts into them.
		 *
		 * Locking prevents further modification of the dropped region during
		 * this transaction, which allows moving the invalidation threshold
		 * without having to worry about new invalidations while
		 * refreshing. */
		for (uint64 i = 0; i < num_chunks; i++)
		{
			LockRelationOid(chunks[i].fd.relid, ExclusiveLock);

			Assert(hyperspace_get_open_dimension(ht->space, 0)->fd.id ==
				   chunks[i].cube->slices[0]->fd.dimension_id);
		}

		DEBUG_WAITPOINT("drop_chunks_locked");

		/* Invalidate the dropped region to indicate that it was modified.
		 *
		 * The invalidation will allow the refresh command on a continuous
		 * aggregate to see that this region was dropped and and will
		 * therefore be able to refresh accordingly.*/
		if (!ts_guc_skip_cagg_invalidation)
		{
			for (uint64 i = 0; i < num_chunks; i++)
			{
				if (osm_chunk_id == chunks[i].fd.id)
				{
					// we do not rebuild continuous aggs if tiered data is dropped */
					continue;
				}
				int64 start = ts_chunk_primary_dimension_start(&chunks[i]);
				int64 end = ts_chunk_primary_dimension_end(&chunks[i]);

				ts_cm_functions->continuous_agg_invalidate_raw_ht(ht, start, end);
			}
		}
	}

	List *dropped_chunk_names = NIL;
	for (uint64 i = 0; i < num_chunks; i++)
	{
		char *chunk_name;

		ASSERT_IS_VALID_CHUNK(&chunks[i]);

		/* frozen chunks are skipped. Not dropped. */
		if (!ts_chunk_validate_chunk_status_for_operation(&chunks[i],
														  CHUNK_DROP,
														  false /*throw_error */) ||
			osm_chunk_id == chunks[i].fd.id)
		{
			continue;
		}

		/* store chunk name for output */
		schema_name = quote_identifier(ts_chunk_get_schema_name(&chunks[i]));
		table_name = quote_identifier(ts_chunk_get_table_name(&chunks[i]));
		chunk_name = psprintf("%s.%s", schema_name, table_name);
		dropped_chunk_names = lappend(dropped_chunk_names, chunk_name);

		ts_chunk_drop(chunks + i, DROP_RESTRICT, log_level);
	}
	// if we have tiered chunks cascade drop to tiering layer as well
	if (osm_chunk_id != INVALID_CHUNK_ID)
	{
		Chunk *osm_chunk = ts_chunk_get_by_id(osm_chunk_id, true);

		hypertable_drop_chunks_hook_type osm_drop_chunks_hook =
			ts_get_osm_hypertable_drop_chunks_hook();

		/*
		 * The OSM library may not be loaded at the moment if
		 * `ts_chunk_do_drop_chunks` is called from the a background worker
		 * (e.g. from a retention policy). We call `GetFdwRoutineByRelId` to
		 * ensure the library is loaded.
		 */
		if (!osm_drop_chunks_hook && GetFdwRoutineByRelId(osm_chunk->fd.relid))
		{
			osm_drop_chunks_hook = ts_get_osm_hypertable_drop_chunks_hook();
		}

		if (osm_drop_chunks_hook)
		{
			ListCell *lc;
			Dimension *dim = &ht->space->dimensions[0];
			/* convert to PG timestamp from timescaledb internal format */
			int64 range_start = ts_internal_to_time_int64(newer_than, dim->fd.column_type);
			int64 range_end = ts_internal_to_time_int64(older_than, dim->fd.column_type);
			List *osm_dropped_names = osm_drop_chunks_hook(osm_chunk->fd.relid,
														   NameStr(ht->fd.schema_name),
														   NameStr(ht->fd.table_name),
														   range_start,
														   range_end);
			foreach (lc, osm_dropped_names)
			{
				dropped_chunk_names = lappend(dropped_chunk_names, lfirst(lc));
			}
		}
	}

	/* When dropping chunks for a given CAgg then force set the watermark */
	if (is_materialization_hypertable)
	{
		bool isnull;
		int64 watermark = ts_hypertable_get_open_dim_max_value(ht, 0, &isnull);
		ts_cagg_watermark_update(ht, watermark, isnull, true);
	}

	DEBUG_WAITPOINT("drop_chunks_end");

	return dropped_chunk_names;
}

/*
 * This is a helper set returning function (SRF) that takes a set returning function context
 * and as argument and returns cstrings extracted from funcctx->user_fctx (which is a List).
 * Note that the caller needs to be registered as a set returning function for this to work.
 */
static Datum
list_return_srf(FunctionCallInfo fcinfo)
{
	FuncCallContext *funcctx;
	uint64 call_cntr;
	TupleDesc tupdesc;
	List *result_set;
	Datum retval;

	/* stuff done only on the first call of the function */
	if (SRF_IS_FIRSTCALL())
	{
		/* Build a tuple descriptor for our result type */
		/* not quite necessary */
		if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_SCALAR)
		{
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("function returning record called in context "
							"that cannot accept type record")));
		}
	}

	/* stuff done on every call of the function */
	funcctx = SRF_PERCALL_SETUP();

	call_cntr = funcctx->call_cntr;
	result_set = castNode(List, funcctx->user_fctx);

	/* do when there is more left to send */
	if (call_cntr < funcctx->max_calls)
	{
		/* store return value and increment linked list */
		retval = CStringGetTextDatum(linitial(result_set));
		funcctx->user_fctx = list_delete_first(result_set);
		SRF_RETURN_NEXT(funcctx, retval);
	}
	else /* do when there is no more left */
	{
		SRF_RETURN_DONE(funcctx);
	}
}

Datum
ts_chunk_drop_single_chunk(PG_FUNCTION_ARGS)
{
	Oid chunk_relid = PG_ARGISNULL(0) ? InvalidOid : PG_GETARG_OID(0);
	if (ts_relation_is_compressed_chunk_relation(chunk_relid))
	{
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("dropping compressed chunks not supported"),
				 errhint("Please drop the corresponding chunk on the uncompressed hypertable "
						 "instead.")));
	}

	char *chunk_table_name = get_rel_name(chunk_relid);
	char *chunk_schema_name = get_namespace_name(get_rel_namespace(chunk_relid));
	ScanTupLock tuplock = {
		.lockmode = LockTupleKeyShare,
		.waitpolicy = LockWaitBlock,
		.lockflags = TUPLE_LOCK_FLAG_FIND_LAST_VERSION,
	};
	const Chunk *ch = ts_chunk_get_by_name_with_memory_context(chunk_schema_name,
															   chunk_table_name,
															   NoLock,
															   &tuplock,
															   CurrentMemoryContext,
															   true);
	Assert(ch != NULL);
	ts_chunk_validate_chunk_status_for_operation(ch, CHUNK_DROP, true /*throw_error */);

	/* do not drop any chunk dependencies */
	ts_chunk_drop(ch, DROP_RESTRICT, LOG);
	PG_RETURN_BOOL(true);
}

/*
 * Drop chunks from a hypertable, dropping everything older than the given boundary.
 *
 * The boundary is either an "older_than" value (matched against the chunk
 * ranges) or, when use_creation_time is set, a "drop_created_before" value
 * (matched against the chunk creation time).
 *
 * Returns the number of dropped chunks.
 */
int
ts_chunk_drop_chunks_by_boundary(Oid relid, Datum older_than, Oid older_than_type,
								 bool use_creation_time)
{
	Cache *hcache = ts_hypertable_cache_pin();
	Hypertable *ht = ts_resolve_hypertable_from_table_or_cagg(hcache, relid, false);
	const Dimension *time_dim = hyperspace_get_open_dimension(ht->space, 0);
	Oid time_type = ts_dimension_get_partition_type(time_dim);
	int64 older_than_internal;
	bool older_newer;
	List *dropped_chunks;
	MemoryContext oldcontext = CurrentMemoryContext;

	/* UUID (v7) partitioning is treated as TIMESTAMPTZ, matching the boundary. */
	if (IS_UUID_TYPE(time_type))
	{
		time_type = TIMESTAMPTZOID;
	}

	if (use_creation_time)
	{
		/* drop_created_before compares against the chunk creation time. */
		int64 created_before =
			ts_time_value_from_arg(older_than, older_than_type, TIMESTAMPTZOID, false);
		older_than_internal = ts_internal_to_time_int64(created_before, TIMESTAMPTZOID);
		older_newer = false;
	}
	else
	{
		older_than_internal = ts_time_value_from_arg(older_than, older_than_type, time_type, true);
		older_newer = true;
	}

	PG_TRY();
	{
		dropped_chunks = ts_chunk_do_drop_chunks(ht,
												 older_than_internal,
												 PG_INT64_MIN,
												 DEBUG2,
												 time_type,
												 older_than_type,
												 older_newer);
	}
	PG_CATCH();
	{
		/* Replace the generic dependent objects hint with an accurate one since
		 * we don't support CASCADE here. */
		ErrorData *edata;

		/* CopyErrorData requires we leave the error context first. */
		MemoryContextSwitchTo(oldcontext);
		edata = CopyErrorData();
		FlushErrorState();

		if (edata->sqlerrcode == ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST)
		{
			edata->hint = pstrdup("Use DROP ... to drop the dependent objects.");
		}

		ts_cache_release(&hcache);
		ReThrowError(edata);
	}
	PG_END_TRY();

	ts_cache_release(&hcache);

	return list_length(dropped_chunks);
}

Datum
ts_chunk_drop_chunks(PG_FUNCTION_ARGS)
{
	MemoryContext oldcontext;
	FuncCallContext *funcctx;
	Hypertable *ht;
	List *dc_temp = NIL;
	List *dc_names = NIL;
	Oid relid = PG_ARGISNULL(0) ? InvalidOid : PG_GETARG_OID(0);

	/*
	 * Marked volatile to suppress the -Wclobbered warning. The warning is
	 * actually incorrect because these values are not used after longjmp.
	 */
	volatile int64 older_than = PG_INT64_MAX;
	volatile int64 newer_than = PG_INT64_MIN;
	volatile int64 created_before = PG_INT64_MAX;
	volatile int64 created_after = PG_INT64_MIN;
	volatile bool older_newer = false;
	volatile bool before_after = false;

	bool verbose;
	int elevel;
	Cache *hcache;
	const Dimension *time_dim;
	Oid time_type;
	Oid arg_type;

	TS_PREVENT_FUNC_IF_READ_ONLY();
	arg_type = InvalidOid;

	/*
	 * When past the first call of the SRF, dropping has already been completed,
	 * so we just return the next chunk in the list of dropped chunks.
	 */
	if (!SRF_IS_FIRSTCALL())
	{
		return list_return_srf(fcinfo);
	}

	if (PG_ARGISNULL(0))
	{
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				 errmsg("invalid hypertable or continuous aggregate"),
				 errhint("Specify a hypertable or continuous aggregate.")));
	}

	/* Find either the hypertable or view, or error out if the relid is
	 * neither.
	 *
	 * We should improve the printout since it can either be a proper relid
	 * that does not refer to a hypertable or a continuous aggregate, or a
	 * relid that does not refer to anything at all. */
	hcache = ts_hypertable_cache_pin();
	ht = ts_resolve_hypertable_from_table_or_cagg(hcache, relid, false);
	Assert(ht != NULL);
	time_dim = hyperspace_get_open_dimension(ht->space, 0);

	if (!time_dim)
	{
		ereport(ERROR,
				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
				 errmsg("hypertable has no open partitioning dimension")));
	}

	time_type = ts_dimension_get_partition_type(time_dim);

	/*
	 * Treat UUID (v7) as a timestamptz type. The expected input is an interval or absolute
	 * timestamptz.
	 */
	if (IS_UUID_TYPE(time_type))
	{
		time_type = TIMESTAMPTZOID;
	}

	/* note that arg_types will be the same for all specified "ANY" elements for a given call */
	if (!PG_ARGISNULL(1))
	{
		arg_type = get_fn_expr_argtype(fcinfo->flinfo, 1);
		older_than = ts_time_value_from_arg(PG_GETARG_DATUM(1), arg_type, time_type, true);
		older_newer = true;
	}

	if (!PG_ARGISNULL(2))
	{
		arg_type = get_fn_expr_argtype(fcinfo->flinfo, 2);
		newer_than = ts_time_value_from_arg(PG_GETARG_DATUM(2), arg_type, time_type, true);
		older_newer = true;
	}

	/*
	 * We cannot have a mix of [older_than/newer_than] and [created_before/created_after].
	 * So, check that first. Note that created_before/created_after have a type of
	 * TIMESTAMPTZOID regardless of the partitioning type.
	 */

	if (!PG_ARGISNULL(4))
	{
		if (older_newer)
		{
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
					 errmsg("cannot specify \"older_than\" or \"newer_than\" together with "
							"\"created_before\""
							"or \"created_after\""),
					 errhint("\"older_than\" and/or \"newer_than\" is recommended with "
							 "\"time\"-like partitioning"
							 " and  \"created_before\" and/or \"created_after\" is recommended "
							 "with \"integer\"-like"
							 " partitioning.")));
		}

		arg_type = get_fn_expr_argtype(fcinfo->flinfo, 4);
		/* We use the existing function for various type/conversion checks */
		created_before =
			ts_time_value_from_arg(PG_GETARG_DATUM(4), arg_type, TIMESTAMPTZOID, false);
		/* convert into int64 format for comparisons */
		created_before = ts_internal_to_time_int64(created_before, TIMESTAMPTZOID);
		before_after = true;
		older_than = created_before;
	}

	if (!PG_ARGISNULL(5))
	{
		if (older_newer)
		{
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
					 errmsg("cannot specify \"older_than\" or \"newer_than\" together with "
							"\"created_before\""
							" or \"created_after\""),
					 errhint("\"older_than\" and/or \"newer_than\" is recommended with "
							 "\"time\"-like partitioning"
							 " and  \"created_before\" and/or \"created_after\" is recommended "
							 "with \"integer\"-like"
							 " partitioning.")));
		}
		arg_type = get_fn_expr_argtype(fcinfo->flinfo, 5);
		/* We use the existing function for various type/conversion checks */
		created_after = ts_time_value_from_arg(PG_GETARG_DATUM(5), arg_type, TIMESTAMPTZOID, false);
		/* convert into int64 format for comparisons */
		created_after = ts_internal_to_time_int64(created_after, TIMESTAMPTZOID);
		before_after = true;
		newer_than = created_after;
	}

	/* if both have not been specified then error out */
	if (!older_newer && !before_after)
	{
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				 errmsg("invalid time range for dropping chunks"),
				 errhint("At least one of older_than/newer_than or created_before/created_after"
						 " must be provided.")));
	}

	/*
	 * For INTEGER type dimensions, we support querying using intervals or any
	 * timestamp or date input. For such INTEGER dimensions, we get the chunks
	 * using their creation time values.
	 */
	if (IS_INTEGER_TYPE(time_type) && (arg_type == INTERVALOID || IS_TIMESTAMP_TYPE(arg_type)))
	{
		/* check that we use proper inputs for such cases */
		if (older_newer)
		{
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
					 errmsg("cannot specify \"older_than\" and/or \"newer_than\" for "
							"\"integer\"-like partitioning types"),
					 errhint("Use \"created_before\" and/or \"created_after\" which rely on the "
							 "chunk creation time values.")));
		}
	}

	verbose = PG_ARGISNULL(3) ? false : PG_GETARG_BOOL(3);
	elevel = verbose ? INFO : DEBUG2;

	/* Initial multi function call setup */
	funcctx = SRF_FIRSTCALL_INIT();

	/* Drop chunks and store their names for return */
	oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);

	PG_TRY();
	{
		dc_temp = ts_chunk_do_drop_chunks(ht,
										  older_than,
										  newer_than,
										  elevel,
										  time_type,
										  arg_type,
										  older_newer);
	}
	PG_CATCH();
	{
		/* An error is raised if there are dependent objects, but the original
		 * message is not very helpful in suggesting that you should use
		 * CASCADE (we don't support it), so we replace the hint with a more
		 * accurate hint for our situation. */
		ErrorData *edata;

		MemoryContextSwitchTo(oldcontext);
		edata = CopyErrorData();
		FlushErrorState();

		if (edata->sqlerrcode == ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST)
		{
			edata->hint = pstrdup("Use DROP ... to drop the dependent objects.");
		}

		ts_cache_release(&hcache);
		ReThrowError(edata);
	}
	PG_END_TRY();
	ts_cache_release(&hcache);
	dc_names = list_concat(dc_names, dc_temp);

	MemoryContextSwitchTo(oldcontext);

	/* store data for multi function call */
	funcctx->max_calls = list_length(dc_names);
	funcctx->user_fctx = dc_names;

	return list_return_srf(fcinfo);
}

/* Return the compression status for the chunk
 */
ChunkCompressionStatus
ts_chunk_get_compression_status(int32 chunk_id)
{
	ChunkCompressionStatus st = CHUNK_COMPRESS_NONE;
	ScanIterator iterator = ts_scan_iterator_create(CHUNK, AccessShareLock, CurrentMemoryContext);
	iterator.ctx.index = catalog_get_index(ts_catalog_get(), CHUNK, CHUNK_ID_INDEX);
	ts_scan_iterator_scan_key_init(&iterator,
								   Anum_chunk_idx_id,
								   BTEqualStrategyNumber,
								   F_INT4EQ,
								   Int32GetDatum(chunk_id));

	ts_scanner_foreach(&iterator)
	{
		TupleInfo *ti = ts_scan_iterator_tuple_info(&iterator);
		bool status_isnull;
		Datum status;

		status = slot_getattr(ti->slot, Anum_chunk_status, &status_isnull);
		Assert(!status_isnull);
		bool status_is_compressed =
			ts_flags_are_set_32(DatumGetInt32(status), CHUNK_STATUS_COMPRESSED);
		bool status_is_unordered =
			ts_flags_are_set_32(DatumGetInt32(status), CHUNK_STATUS_COMPRESSED_UNORDERED);
		bool status_is_partial =
			ts_flags_are_set_32(DatumGetInt32(status), CHUNK_STATUS_COMPRESSED_PARTIAL);
		if (status_is_compressed)
		{
			if (status_is_unordered || status_is_partial)
			{
				st = CHUNK_COMPRESS_UNORDERED;
			}
			else
			{
				st = CHUNK_COMPRESS_ORDERED;
			}
		}
		else
		{
			Assert(!status_is_unordered);
			st = CHUNK_COMPRESS_NONE;
		}
	}
	ts_scan_iterator_close(&iterator);
	return st;
}

/* Note that only a compressed chunk can have unordered flag set */
bool
ts_chunk_is_unordered(const Chunk *chunk)
{
	return ts_flags_are_set_32(chunk->fd.status, CHUNK_STATUS_COMPRESSED_UNORDERED);
}

bool
ts_chunk_is_compressed(const Chunk *chunk)
{
	return ts_flags_are_set_32(chunk->fd.status, CHUNK_STATUS_COMPRESSED);
}

bool
ts_chunk_needs_compression(const Chunk *chunk)
{
	return !ts_chunk_is_compressed(chunk);
}

bool
ts_chunk_needs_recompression(const Chunk *chunk)
{
	Assert(ts_chunk_is_compressed(chunk));
	return ts_chunk_is_partial(chunk) || ts_chunk_is_unordered(chunk);
}

/* Note that only a compressed chunk can have partial flag set */
bool
ts_chunk_is_partial(const Chunk *chunk)
{
	return ts_flags_are_set_32(chunk->fd.status, CHUNK_STATUS_COMPRESSED_PARTIAL);
}

static const char *
get_chunk_operation_str(ChunkOperation cmd)
{
	switch (cmd)
	{
		case CHUNK_INSERT:
			return "Insert";
		case CHUNK_DELETE:
			return "Delete";
		case CHUNK_UPDATE:
			return "Update";
		case CHUNK_COMPRESS:
			return "compress_chunk";
		case CHUNK_DECOMPRESS:
			return "decompress_chunk";
		case CHUNK_DROP:
			return "drop_chunk";
		default:
			return "Unsupported";
	}
}

bool
ts_chunk_validate_chunk_status_for_operation(const Chunk *chunk, ChunkOperation cmd,
											 bool throw_error)
{
	Oid chunk_relid = chunk->fd.relid;
	int32 chunk_status = chunk->fd.status;

	/*
	 * Block everything but DELETE on OSM chunks.
	 */
	if (chunk->fd.osm_chunk)
	{
		switch (cmd)
		{
			case CHUNK_DROP:
				return true;
				break;

			default:
				if (throw_error)
				{
					ereport(ERROR,
							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
							 errmsg("%s not permitted on tiered chunk \"%s\" ",
									get_chunk_operation_str(cmd),
									get_rel_name(chunk_relid))));
				}
				return false;
				break;
		}
	}

	/* Handle frozen chunks */
	if (ts_flags_are_set_32(chunk_status, CHUNK_STATUS_FROZEN))
	{
		/* Data modification is not permitted on a frozen chunk */
		switch (cmd)
		{
			case CHUNK_INSERT:
			case CHUNK_DELETE:
			case CHUNK_UPDATE:
			case CHUNK_COMPRESS:
			case CHUNK_DECOMPRESS:
			case CHUNK_DROP:
			{
				if (throw_error)
				{
					ereport(ERROR,
							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
							 errmsg("%s not permitted on frozen chunk \"%s\" ",
									get_chunk_operation_str(cmd),
									get_rel_name(chunk_relid))));
				}
				return false;
				break;
			}
			default:
				break; /*supported operations */
		}
	}
	/* Handle unfrozen chunks */
	else
	{
		switch (cmd)
		{
			/* supported operations */
			case CHUNK_INSERT:
			case CHUNK_DELETE:
			case CHUNK_UPDATE:
				break;
			/* Only uncompressed chunks can be compressed */
			case CHUNK_COMPRESS:
			{
				if (ts_flags_are_set_32(chunk_status, CHUNK_STATUS_COMPRESSED))
				{
					ereport((throw_error ? ERROR : NOTICE),
							(errcode(ERRCODE_DUPLICATE_OBJECT),
							 errmsg("chunk \"%s\" is already compressed",
									get_rel_name(chunk_relid))));
				}
				return false;
			}
			/* Only compressed chunks can be decompressed */
			case CHUNK_DECOMPRESS:
			{
				if (!ts_flags_are_set_32(chunk_status, CHUNK_STATUS_COMPRESSED))
				{
					ereport((throw_error ? ERROR : NOTICE),
							(errcode(ERRCODE_DUPLICATE_OBJECT),
							 errmsg("chunk \"%s\" is already decompressed",
									get_rel_name(chunk_relid))));
				}
				return false;
			}
			default:
				break;
		}
	}

	return true;
}

Datum
ts_chunk_show(PG_FUNCTION_ARGS)
{
	return ts_cm_functions->show_chunk(fcinfo);
}

Datum
ts_chunk_create(PG_FUNCTION_ARGS)
{
	return ts_cm_functions->create_chunk(fcinfo);
}

/**
 * Get the chunk status.
 *
 * Values returned are documented above and is a bitwise or of the
 * CHUNK_STATUS_XXX values.
 *
 * @see CHUNK_STATUS_DEFAULT
 * @see CHUNK_STATUS_COMPRESSED
 * @see CHUNK_STATUS_COMPRESSED_UNORDERED
 * @see CHUNK_STATUS_FROZEN
 * @see CHUNK_STATUS_COMPRESSED_PARTIAL
 */
Datum
ts_chunk_status(PG_FUNCTION_ARGS)
{
	Oid chunk_relid = PG_GETARG_OID(0);
	Chunk *chunk = ts_chunk_get_by_relid(chunk_relid, /* fail_if_not_found */ true);
	PG_RETURN_INT32(chunk->fd.status);
}

TS_FUNCTION_INFO_V1(ts_chunk_status_text);

Datum
ts_chunk_status_text(PG_FUNCTION_ARGS)
{
	int32 status = PG_GETARG_INT32(0);

	ArrayBuildState *astate = initArrayResult(TEXTOID, CurrentMemoryContext, false);

	if (status & CHUNK_STATUS_COMPRESSED)
	{
		astate = accumArrayResult(astate,
								  CStringGetTextDatum("COMPRESSED"),
								  false,
								  TEXTOID,
								  CurrentMemoryContext);
	}

	if (status & CHUNK_STATUS_COMPRESSED_UNORDERED)
	{
		astate = accumArrayResult(astate,
								  CStringGetTextDatum("UNORDERED"),
								  false,
								  TEXTOID,
								  CurrentMemoryContext);
	}

	if (status & CHUNK_STATUS_FROZEN)
	{
		astate = accumArrayResult(astate,
								  CStringGetTextDatum("FROZEN"),
								  false,
								  TEXTOID,
								  CurrentMemoryContext);
	}

	if (status & CHUNK_STATUS_COMPRESSED_PARTIAL)
	{
		astate = accumArrayResult(astate,
								  CStringGetTextDatum("PARTIAL"),
								  false,
								  TEXTOID,
								  CurrentMemoryContext);
	}

	if (status < 0 || status > (CHUNK_STATUS_COMPRESSED | CHUNK_STATUS_COMPRESSED_UNORDERED |
								CHUNK_STATUS_FROZEN | CHUNK_STATUS_COMPRESSED_PARTIAL))
	{
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				 errmsg("invalid chunk status %d", status)));
	}

	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
}

/*
 * Lock the chunk if the lockmode demands it.
 *
 * Also check that the chunk relation actually exists after the lock is
 * acquired. Return true if no locking is necessary or the chunk relation
 * exists and the lock was successfully acquired. Otherwise return false.
 */
bool
ts_chunk_lock_if_exists(Oid chunk_oid, LOCKMODE chunk_lockmode)
{
	/* No lock is requested, so assume relation exists */
	if (chunk_lockmode != NoLock)
	{
		/* Get the lock to synchronize against concurrent drop */
		LockRelationOid(chunk_oid, chunk_lockmode);

		/*
		 * Now that we have the lock, double-check to see if the relation
		 * really exists or not.  If not, assume it was dropped while we
		 * waited to acquire lock, and ignore it.
		 */
		if (!SearchSysCacheExists1(RELOID, ObjectIdGetDatum(chunk_oid)))
		{
			/* Release useless lock */
			UnlockRelationOid(chunk_oid, chunk_lockmode);
			/* And ignore this relation */
			return false;
		}
	}

	return true;
}

ScanIterator
ts_chunk_scan_iterator_create(MemoryContext result_mcxt)
{
	ScanIterator it = ts_scan_iterator_create(CHUNK, AccessShareLock, result_mcxt);
	it.ctx.flags |= SCANNER_F_NOEND_AND_NOCLOSE;

	return it;
}

void
ts_chunk_scan_iterator_set_chunk_id(ScanIterator *it, int32 chunk_id)
{
	it->ctx.index = catalog_get_index(ts_catalog_get(), CHUNK, CHUNK_ID_INDEX);
	ts_scan_iterator_scan_key_reset(it);
	ts_scan_iterator_scan_key_init(it,
								   Anum_chunk_idx_id,
								   BTEqualStrategyNumber,
								   F_INT4EQ,
								   Int32GetDatum(chunk_id));
}

/*
 * Create a hypercube for the OSM chunk
 * The initial range for the OSM chunk will be from INT64_MAX - 1 to INT64_MAX.
 * This range was chosen to minimize interference with tuple routing and
 * occupy a range outside of potential values as there must be no overlap
 * between the hypercube occupied by the osm chunk and actual chunks.
 */
static Hypercube *
fill_hypercube_for_osm_chunk(Hyperspace *hs)
{
	Hypercube *cube = ts_hypercube_alloc(hs->num_dimensions);
	Assert(hs->num_dimensions == 1); // does not work with partitioned range
	for (int i = 0; i < hs->num_dimensions; i++)
	{
		const Dimension *dim = &hs->dimensions[i];
		Assert(dim->type == DIMENSION_TYPE_OPEN);
		cube->slices[i] = ts_dimension_slice_create(dim->fd.id, PG_INT64_MAX - 1, PG_INT64_MAX);
		cube->num_slices++;
	}
	Assert(cube->num_slices == 1);
	return cube;
}

/* adds foreign table as a chunk to the hypertable.
 * creates a dummy chunk constraint for the time dimension.
 * These constraints are recorded in the chunk-dimension slice metadata.
 * They are NOT added as CHECK constraints on the foreign table.
 *
 * Does not add any inheritable constraints or indexes that are already
 * defined on the hypertable.
 *
 * This is used to add an OSM table as a chunk.
 * Set the osm_chunk flag to true.
 */
static void
add_foreign_table_as_chunk(Oid relid, Hypertable *parent_ht)
{
	Hyperspace *hs = parent_ht->space;
	Catalog *catalog = ts_catalog_get();
	CatalogSecurityContext sec_ctx;
	Chunk *chunk;

	Oid ht_ownerid = ts_rel_get_owner(parent_ht->main_table_relid);

	if (!ts_has_owner_privs(GetUserId(), ht_ownerid))
	{
		ereport(ERROR,
				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
				 errmsg("must be owner of hypertable \"%s\"",
						get_rel_name(parent_ht->main_table_relid))));
	}

	Assert(get_rel_relkind(relid) == RELKIND_FOREIGN_TABLE);
	if (hs->num_dimensions > 1)
	{
		elog(ERROR,
			 "cannot attach a  foreign table to a hypertable that has more than 1 dimension");
	}
	/* Create a new chunk based on the hypercube */
	ts_catalog_database_info_become_owner(ts_catalog_database_info_get(), &sec_ctx);
	chunk = ts_chunk_create_base(ts_catalog_table_next_seq_id(catalog, CHUNK));
	ts_catalog_restore_user(&sec_ctx);

	/* fill in the correct table_name for the chunk*/
	chunk->fd.hypertable_id = hs->hypertable_id;
	chunk->fd.osm_chunk = true; /* this is an OSM chunk */
	chunk->cube = fill_hypercube_for_osm_chunk(hs);
	chunk->hypertable_relid = parent_ht->main_table_relid;
	chunk->fd.relid = relid;
	chunk->relkind = RELKIND_FOREIGN_TABLE;

	/* Insert chunk */
	ts_chunk_insert_lock(chunk, RowExclusiveLock);

	/* Stamp the new chunk id on each cube slice before inserting them. */
	prepare_cube_slices_for_chunk(chunk->cube, chunk->fd.id);
	ts_dimension_slice_insert_multi(chunk->cube->slices, chunk->cube->num_slices);
	/* CHECK constraints are not inherited automatically by foreign tables, so
	 * clone them from the hypertable onto the foreign chunk before running
	 * ALTER TABLE ... INHERIT below.
	 */
	ts_chunk_clone_check_constraints(relid, chunk->hypertable_relid);
	chunk_create_table_constraints(parent_ht, chunk);
	chunk_add_inheritance(chunk, parent_ht);
	/*
	 * Update hypertable entry with tiering status information.
	 * XXX: For compatibility reasons, we set the noncontiguous flag, but
	 * this should be reverted as soon as the newer version of the OSM extension
	 * is rolled out.
	 * Noncontiguous flag should not be set since the chunk should be empty upon
	 * creation, with an invalid range assigned, so ordered append should be allowed.
	 * Once the data is moved into the OSM chunk, then our catalog should be
	 * updated with proper API calls from the OSM extension.
	 */
	ts_hypertable_add_status(parent_ht,
							 HYPERTABLE_STATUS_OSM | HYPERTABLE_STATUS_OSM_CHUNK_NONCONTIGUOUS);
}

void
ts_chunk_merge_on_dimension(const Hypertable *ht, Chunk *chunk, const Chunk *merge_chunk,
							int32 dimension_id)
{
	const DimensionSlice *slice, *merge_slice;
	bool dimension_slice_found = false;

	if (chunk->hypertable_relid != merge_chunk->hypertable_relid)
	{
		ereport(ERROR,
				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
				 errmsg("cannot merge chunks from different hypertables"),
				 errhint("chunk 1: \"%s\", chunk 2: \"%s\"",
						 get_rel_name(chunk->fd.relid),
						 get_rel_name(merge_chunk->fd.relid))));
	}

	for (int i = 0; i < chunk->cube->num_slices; i++)
	{
		if (chunk->cube->slices[i]->fd.dimension_id == dimension_id)
		{
			slice = chunk->cube->slices[i];
			merge_slice = merge_chunk->cube->slices[i];
			dimension_slice_found = true;
		}
		else if (!ts_dimension_slices_equal(chunk->cube->slices[i], merge_chunk->cube->slices[i]))
		{
			ereport(ERROR,
					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
					 errmsg("cannot merge chunks with different partitioning schemas"),
					 errhint("chunk 1: \"%s\", chunk 2: \"%s\" have different slices on "
							 "dimension ID %d",
							 get_rel_name(chunk->fd.relid),
							 get_rel_name(merge_chunk->fd.relid),
							 chunk->cube->slices[i]->fd.dimension_id)));
		}
	}

	if (!dimension_slice_found)
	{
		ereport(ERROR,
				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
				 errmsg("cannot find slice for merging dimension"),
				 errhint("chunk 1: \"%s\", chunk 2: \"%s\", dimension ID %d",
						 get_rel_name(chunk->fd.relid),
						 get_rel_name(merge_chunk->fd.relid),
						 dimension_id)));
	}

	if (slice->fd.range_end != merge_slice->fd.range_start)
	{
		ereport(ERROR,
				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
				 errmsg("cannot merge non-adjacent chunks over supplied dimension"),
				 errhint("chunk 1: \"%s\", chunk 2: \"%s\", dimension ID %d",
						 get_rel_name(chunk->fd.relid),
						 get_rel_name(merge_chunk->fd.relid),
						 dimension_id)));
	}

	int32 old_slice_id = slice->fd.id;
	DimensionSlice *new_slice =
		ts_dimension_slice_create(dimension_id, slice->fd.range_start, merge_slice->fd.range_end);

	/* Replace the kept chunk's slice with the merged range. */
	ts_dimension_slice_delete_by_id(old_slice_id);
	new_slice->fd.chunk_id = chunk->fd.id;
	ts_dimension_slice_insert(new_slice);

	/* Reflect the new slice in the in-memory hypercube so the recreate path
	 * below builds the right CHECK. */
	for (int i = 0; i < chunk->cube->num_slices; i++)
	{
		if (chunk->cube->slices[i]->fd.dimension_id == dimension_id)
		{
			chunk->cube->slices[i] = new_slice;
			break;
		}
	}

	/* Drop the CHECK on the chunk table that came from the old slice. Its name
	 * is derived from the slice id. */
	char old_check_name[NAMEDATALEN];
	snprintf(old_check_name, NAMEDATALEN, "constraint_%d", old_slice_id);
	Oid old_check_oid = get_relation_constraint_oid(chunk->fd.relid, old_check_name, true);
	if (OidIsValid(old_check_oid))
	{
		ObjectAddress constrobj = {
			.classId = ConstraintRelationId,
			.objectId = old_check_oid,
		};
		performDeletion(&constrobj, DROP_RESTRICT, 0);
	}

	/* Build an in-memory constraint entry for the new slice and let the
	 * existing helper create the CHECK on the chunk table. */
	ts_process_utility_set_expect_chunk_modification(true);
	ts_chunk_constraints_create(ht, chunk);
	ts_chunk_copy_referencing_fk(ht, chunk);
	ts_process_utility_set_expect_chunk_modification(false);

	ts_chunk_drop(merge_chunk, DROP_RESTRICT, 1);
}

/* Internal API used by OSM extension. OSM table is a foreign table that is
 * attached as a chunk of the hypertable. A chunk needs dimension constraints. We
 * add dummy constraints for the OSM chunk and then attach it to the hypertable.
 * OSM extension is responsible for maintaining any constraints on this table.
 */
Datum
ts_chunk_attach_osm_table_chunk(PG_FUNCTION_ARGS)
{
	Oid hypertable_relid = PG_ARGISNULL(0) ? InvalidOid : PG_GETARG_OID(0);
	Oid ftable_relid = PG_ARGISNULL(1) ? InvalidOid : PG_GETARG_OID(1);
	bool ret = false;

	Cache *hcache;
	Hypertable *ht =
		ts_hypertable_cache_get_cache_and_entry(hypertable_relid, CACHE_FLAG_MISSING_OK, &hcache);

	if (!ht)
	{
		char *name = get_rel_name(hypertable_relid);

		if (!name)
		{
			ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("invalid Oid")));
		}
		else
		{
			ereport(ERROR,
					(errcode(ERRCODE_TS_HYPERTABLE_NOT_EXIST),
					 errmsg("\"%s\" is not a hypertable", name)));
		}
	}

	if (get_rel_relkind(ftable_relid) == RELKIND_FOREIGN_TABLE)
	{
		add_foreign_table_as_chunk(ftable_relid, ht);
		ret = true;
	}
	ts_cache_release(&hcache);

	PG_RETURN_BOOL(ret);
}

static ScanTupleResult
chunk_tuple_osm_chunk_found(TupleInfo *ti, void *arg)
{
	bool isnull;
	Datum osm_chunk = slot_getattr(ti->slot, Anum_chunk_osm_chunk, &isnull);

	Assert(!isnull);
	bool is_osm_chunk = DatumGetBool(osm_chunk);

	if (!is_osm_chunk)
	{
		return SCAN_CONTINUE;
	}

	int *chunk_id = (int *) arg;
	Datum chunk_id_datum = slot_getattr(ti->slot, Anum_chunk_id, &isnull);
	Assert(!isnull);
	*chunk_id = DatumGetInt32(chunk_id_datum);
	return SCAN_DONE;
}

/* get OSM chunk id associated with the hypertable */
int
ts_chunk_get_osm_chunk_id(int hypertable_id)
{
	int chunk_id = INVALID_CHUNK_ID;
	ScanKeyData scankey[2];
	bool is_osm_chunk = true;
	Catalog *catalog = ts_catalog_get();
	ScannerCtx scanctx = {
		.table = catalog_get_table_id(catalog, CHUNK),
		.index = catalog_get_index(catalog, CHUNK, CHUNK_OSM_CHUNK_INDEX),
		.nkeys = 2,
		.scankey = scankey,
		.data = &chunk_id,
		.tuple_found = chunk_tuple_osm_chunk_found,
		.lockmode = AccessShareLock,
		.scandirection = ForwardScanDirection,
	};

	/*
	 * Perform an index scan on hypertable ID + osm_chunk
	 */
	ScanKeyInit(&scankey[0],
				Anum_chunk_osm_chunk_idx_osm_chunk,
				BTEqualStrategyNumber,
				F_BOOLEQ,
				BoolGetDatum(is_osm_chunk));
	ScanKeyInit(&scankey[1],
				Anum_chunk_osm_chunk_idx_hypertable_id,
				BTEqualStrategyNumber,
				F_INT4EQ,
				Int32GetDatum(hypertable_id));

	int num_found = ts_scanner_scan(&scanctx);

	if (num_found > 1)
	{
		ereport(ERROR,
				(errcode(ERRCODE_INTERNAL_ERROR),
				 errmsg("More than 1 OSM chunk found for hypertable (%d)", hypertable_id)));
	}

	return chunk_id;
}

/* Upon creation, OSM chunks are assigned an invalid range [INT64_MAX -1, infinity) */
bool
ts_osm_chunk_range_is_invalid(int64 range_start, int64 range_end)
{
	return ((range_end == PG_INT64_MAX) && (range_start == range_end - 1));
}

/*
 * Initialization and access method for ChunkVec. This needs to be extended to support additional
 * operations.
 */
static ChunkVec *
chunk_vec_expand(ChunkVec *chunks, uint32 new_capacity)
{
	if (chunks != NULL && chunks->capacity >= new_capacity)
	{
		return chunks;
	}

	if (chunks == NULL)
	{
		chunks = palloc(CHUNK_VEC_SIZE(new_capacity));
	}
	else
	{
		chunks = repalloc(chunks, CHUNK_VEC_SIZE(new_capacity));
	}

	chunks->capacity = new_capacity;

	return chunks;
}

ChunkVec *
ts_chunk_vec_create(int32 capacity)
{
	ChunkVec *chunks = chunk_vec_expand(NULL, capacity);

	chunks->num_chunks = 0;
	return chunks;
}

ChunkVec *
ts_chunk_vec_sort(ChunkVec **chunks)
{
	ChunkVec *vec = *chunks;

	if (vec->num_chunks > 1)
	{
		qsort(&vec->chunks, vec->num_chunks, sizeof(Chunk), chunk_cmp);
	}

	return vec;
}

ChunkVec *
ts_chunk_vec_add_from_tuple(ChunkVec **chunks, TupleInfo *ti)
{
	Chunk *chunkptr = NULL;
	ChunkVec *vec;

	vec = *chunks;

	if (vec->num_chunks + 1 > vec->capacity)
	{
		*chunks = vec = chunk_vec_expand(vec, vec->capacity + DEFAULT_CHUNK_VEC_SIZE);
	}

	chunkptr = &vec->chunks[vec->num_chunks++];
	ts_chunk_formdata_fill(&chunkptr->fd, ti);

	/* Build the cube from dimension_slice rows owned by this chunk. */
	{
		List *slices = ts_dimension_slice_scan_by_chunk_id(chunkptr->fd.id, ti->mctx);
		ListCell *lc;
		MemoryContext oldctx = MemoryContextSwitchTo(ti->mctx);

		chunkptr->cube = ts_hypercube_alloc(list_length(slices));
		MemoryContextSwitchTo(oldctx);
		foreach (lc, slices)
		{
			chunkptr->cube->slices[chunkptr->cube->num_slices++] = (DimensionSlice *) lfirst(lc);
		}
		ts_hypercube_slice_sort(chunkptr->cube);
	}

	chunkptr->hypertable_relid = ts_hypertable_id_to_relid(chunkptr->fd.hypertable_id, false);
	chunkptr->relkind = get_rel_relkind(chunkptr->fd.relid);

	return vec;
}

/*
 * Prepare for an index scan for all the chunks matching the given hypertable_id and range criteria.
 */
static int
chunk_creation_time_set_range(ScanIterator *it, Oid hypertable_id, StrategyNumber start_strategy,
							  int64 start_value, StrategyNumber end_strategy, int64 end_value)
{
	TypeCacheEntry *tce;

	it->ctx.index =
		catalog_get_index(ts_catalog_get(), CHUNK, CHUNK_HYPERTABLE_ID_CREATION_TIME_INDEX);
	ts_scan_iterator_scan_key_reset(it);

	ts_scan_iterator_scan_key_init(it,
								   Anum_chunk_hypertable_id_creation_time_idx_hypertable_id,
								   BTEqualStrategyNumber,
								   F_INT4EQ,
								   Int32GetDatum(hypertable_id));

	tce = lookup_type_cache(TIMESTAMPTZOID, TYPECACHE_BTREE_OPFAMILY);

	/* If both are valid strategies then a proper scan within these limits will be performed */
	if (start_strategy != InvalidStrategy)
	{
		Oid opno =
			get_opfamily_member(tce->btree_opf, TIMESTAMPTZOID, TIMESTAMPTZOID, start_strategy);
		Oid proc = get_opcode(opno);

		Assert(OidIsValid(proc));

		ts_scan_iterator_scan_key_init(it,
									   Anum_chunk_hypertable_id_creation_time_idx_creation_time,
									   start_strategy,
									   proc,
									   Int64GetDatum(start_value));
	}
	if (end_strategy != InvalidStrategy)
	{
		Oid opno =
			get_opfamily_member(tce->btree_opf, TIMESTAMPTZOID, TIMESTAMPTZOID, end_strategy);
		Oid proc = get_opcode(opno);

		Assert(OidIsValid(proc));

		ts_scan_iterator_scan_key_init(it,
									   Anum_chunk_hypertable_id_creation_time_idx_creation_time,
									   end_strategy,
									   proc,
									   Int64GetDatum(end_value));
	}

	return it->ctx.nkeys;
}

/*
 * Perform an index scan for given hypertable_id and chunk creation time range.
 *
 * Returns an array of chunks using ChunkVec the encloses all the chunks satisfying the range
 * criteria.
 */
static Chunk *
get_chunks_in_creation_time_range_limit(Hypertable *ht, StrategyNumber start_strategy,
										int64 start_value, StrategyNumber end_strategy,
										int64 end_value, int limit, uint64 *num_chunks,
										ScanTupLock *tupLock)
{
	ScanIterator it;
	ChunkVec *chunk_vec = NULL;

	it = ts_scan_iterator_create(CHUNK, AccessShareLock, CurrentMemoryContext);
	it.ctx.flags |= SCANNER_F_NOEND_AND_NOCLOSE;
	it.ctx.tuplock = tupLock;

	chunk_creation_time_set_range(&it,
								  ht->fd.id,
								  start_strategy,
								  start_value,
								  end_strategy,
								  end_value);
	it.ctx.limit = limit;

#ifdef TS_DEBUG
	/* allow testing of the chunk vec expansion in debug builds */
	if (limit == -1)
	{
		limit = 1;
	}
#endif

	chunk_vec = ts_chunk_vec_create(limit > 0 ? limit : DEFAULT_CHUNK_VEC_SIZE);

	ts_scanner_foreach(&it)
	{
		TupleInfo *ti = ts_scan_iterator_tuple_info(&it);
		ts_chunk_vec_add_from_tuple(&chunk_vec, ti);
	}

	ts_scan_iterator_close(&it);

	ts_chunk_vec_sort(&chunk_vec);

	*num_chunks = chunk_vec->num_chunks;

	return chunk_vec->chunks;
}

Chunk *
get_chunks_in_creation_time_range(Hypertable *ht, int64 older_than, int64 newer_than,
								  MemoryContext mctx, uint64 *num_chunks_returned,
								  ScanTupLock *tupLock)
{
	MemoryContext oldcontext;
	Chunk *chunks = NULL;
	StrategyNumber start_strategy;
	StrategyNumber end_strategy;
	uint64 num_chunks = 0;

	if (older_than <= newer_than)
	{
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				 errmsg("invalid chunk creation time range"),
				 errhint("The start of the time range must be before the end.")));
	}

	start_strategy = (newer_than == PG_INT64_MIN) ? InvalidStrategy : BTGreaterEqualStrategyNumber;
	end_strategy = (older_than == PG_INT64_MAX) ? InvalidStrategy : BTLessStrategyNumber;

	oldcontext = MemoryContextSwitchTo(mctx);
	chunks = get_chunks_in_creation_time_range_limit(ht,
													 start_strategy,
													 newer_than,
													 end_strategy,
													 older_than,
													 -1,
													 &num_chunks,
													 tupLock);
	MemoryContextSwitchTo(oldcontext);
	*num_chunks_returned = num_chunks;

	return chunks;
}

Datum
ts_chunk_drop_osm_chunk(PG_FUNCTION_ARGS)
{
	Oid hypertable_relid = PG_ARGISNULL(0) ? InvalidOid : PG_GETARG_OID(0);
	Cache *hcache = ts_hypertable_cache_pin();
	Hypertable *ht = ts_resolve_hypertable_from_table_or_cagg(hcache, hypertable_relid, true);
	int32 osm_chunk_id = ts_chunk_get_osm_chunk_id(ht->fd.id);
	Chunk *osm_chunk = ts_chunk_get_by_id(osm_chunk_id, true);

	ts_chunk_validate_chunk_status_for_operation(osm_chunk, CHUNK_DROP, true);

	/* do not drop any chunk dependencies */
	ts_chunk_drop(osm_chunk, DROP_RESTRICT, LOG);

	/* reset hypertable OSM status */
	ts_hypertable_clear_status(ht,
							   HYPERTABLE_STATUS_OSM | HYPERTABLE_STATUS_OSM_CHUNK_NONCONTIGUOUS);
	ts_cache_release(&hcache);
	PG_RETURN_BOOL(true);
}

TS_FUNCTION_INFO_V1(ts_merge_two_chunks);

Datum
ts_merge_two_chunks(PG_FUNCTION_ARGS)
{
	Datum chunks[2] = { PG_GETARG_DATUM(0), PG_GETARG_DATUM(1) };
	bool concurrently = PG_ARGISNULL(2) ? false : PG_GETARG_BOOL(2);
	ArrayType *chunk_array =
		construct_array(chunks, 2, REGCLASSOID, sizeof(Oid), true, TYPALIGN_INT);
	return DirectFunctionCall2(ts_cm_functions->merge_chunks,
							   PointerGetDatum(chunk_array),
							   BoolGetDatum(concurrently));
}

TS_FUNCTION_INFO_V1(ts_merge_chunks_concurrently);

Datum
ts_merge_chunks_concurrently(PG_FUNCTION_ARGS)
{
	return DirectFunctionCall2(ts_cm_functions->merge_chunks,
							   PG_GETARG_DATUM(0),
							   BoolGetDatum(true));
}

void
ts_chunk_detach_by_relid(Oid relid)
{
	ScanIterator iterator = ts_scan_iterator_create(CHUNK, RowExclusiveLock, CurrentMemoryContext);
	int PG_USED_FOR_ASSERTS_ONLY count;

	Assert(OidIsValid(relid));

	init_scan_by_relid(&iterator, relid);
	count = chunk_delete(&iterator, relid, DROP_RESTRICT, true);

	/* relid is unique so should only have dropped one chunk */
	Assert(count == 1);
}