Disable direct compress for tables with exclusion constraints

.unreleased/fix_direct_compress_exclusion

@@ -0,0 +1 @@
+Fixes: #10281 Disable Direct Compress when the destination table has an exclusion constraint so the constraint is still enforced

src/copy.c

@@ -845,6 +845,12 @@ choose_copy_method(Hypertable *ht, CopyChunkState *ccstate, ResultRelInfo *resul
 					(errmsg("disabling direct compress because the destination table has unique "
 							"constraints")));
 		}
+		else if (ts_indexing_relation_has_exclusion_constraint(ccstate->rel))
+		{
+			ereport(WARNING,
+					(errmsg("disabling direct compress because the destination table has exclusion "
+							"constraints")));
+		}
 		else if (resultRelInfo->ri_TrigDesc && resultRelInfo->ri_TrigDesc->numtriggers > 1)
 		{
 			ereport(WARNING,

src/indexing.c

@@ -337,6 +337,40 @@ ts_indexing_relation_has_primary_or_unique_index(Relation htrel)
 	return result;
 }
 
+bool TSDLLEXPORT
+ts_indexing_relation_has_exclusion_constraint(Relation htrel)
+{
+	List *indexoidlist = RelationGetIndexList(htrel);
+	ListCell *lc;
+	bool result = false;
+
+	foreach (lc, indexoidlist)
+	{
+		Oid indexoid = lfirst_oid(lc);
+		HeapTuple index_tuple;
+		Form_pg_index index;
+
+		index_tuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(indexoid));
+		if (!HeapTupleIsValid(index_tuple)) /* should not happen */
+		{
+			elog(ERROR,
+				 "cache lookup failed for index %u in \"%s\" ",
+				 indexoid,
+				 RelationGetRelationName(htrel));
+		}
+		index = (Form_pg_index) GETSTRUCT(index_tuple);
+		result = index->indisexclusion;
+		ReleaseSysCache(index_tuple);
+		if (result)
+		{
+			break;
+		}
+	}
+
+	list_free(indexoidlist);
+	return result;
+}
+
 /*
  * Collect the heap attribute numbers covered by any valid unique index
  * (PRIMARY KEY included) on the relation. Returns a Bitmapset of raw attribute

src/indexing.h

@@ -24,6 +24,7 @@ extern TSDLLEXPORT Oid ts_indexing_find_clustered_index(Oid table_relid);
 extern void ts_indexing_mark_as_valid(Oid index_id);
 extern bool ts_indexing_mark_as_invalid(Oid index_id);
 extern bool TSDLLEXPORT ts_indexing_relation_has_primary_or_unique_index(Relation htrel);
+extern bool TSDLLEXPORT ts_indexing_relation_has_exclusion_constraint(Relation htrel);
 extern TSDLLEXPORT Bitmapset *ts_indexing_relation_get_unique_columns(Relation rel);
 extern TSDLLEXPORT bool ts_indexing_compare(Oid index1, Oid index2);
 extern TSDLLEXPORT Datum ts_index_matches(PG_FUNCTION_ARGS);

src/nodes/modify_hypertable.c

@@ -61,6 +61,14 @@ should_use_direct_compress(ModifyHypertableState *state)
 		return false;
 	}
 
+	if (ts_indexing_relation_has_exclusion_constraint(state->ctr->root_rel))
+	{
+		ereport(WARNING,
+				(errmsg("disabling direct compress because the destination table has exclusion "
+						"constraints")));
+		return false;
+	}
+
 	Plan *subplan = mtstate->ps.plan->lefttree;
 	if (subplan->plan_rows < 10)
 	{

tsl/test/expected/direct_compress_insert.out

@@ -932,3 +932,32 @@ SELECT count(*), min(value), max(value) FROM metrics_view;
 RESET timescaledb.enable_direct_compress_insert;
 DROP VIEW metrics_view_pos;
 DROP TABLE metrics_view;
+-- Direct compress must be disabled when the table has an exclusion constraint
+CREATE TABLE dc_excl(time timestamptz NOT NULL, device text NOT NULL, value float,
+    EXCLUDE USING btree (time WITH =, device WITH =))
+    WITH (tsdb.hypertable, tsdb.partition_column='time');
+ALTER TABLE dc_excl SET (timescaledb.compress, timescaledb.compress_segmentby='device');
+NOTICE:  updated compression settings will only apply to future compressions
+SET timescaledb.enable_direct_compress_insert = true;
+-- insert warns, disables direct compress and falls back to a normal insert
+INSERT INTO dc_excl SELECT '2025-01-01'::timestamptz + (i || ' minute')::interval, 'd1', i::float FROM generate_series(1,100) i;
+WARNING:  disabling direct compress because the destination table has exclusion constraints
+-- chunk stays uncompressed since direct compress was disabled
+SELECT DISTINCT _timescaledb_functions.chunk_status_text(chunk) FROM show_chunks('dc_excl') chunk;
+ chunk_status_text 
+-------------------
+ {}
+
+-- exclusion constraint is still enforced
+\set ON_ERROR_STOP 0
+INSERT INTO dc_excl VALUES ('2025-01-01'::timestamptz + INTERVAL '1 minute', 'd1', 99);
+WARNING:  disabling direct compress because the destination table has exclusion constraints
+ERROR:  conflicting key value violates exclusion constraint "62_dc_excl_time_device_excl"
+\set ON_ERROR_STOP 1
+SELECT count(*) FROM dc_excl;
+ count 
+-------
+   100
+
+RESET timescaledb.enable_direct_compress_insert;
+DROP TABLE dc_excl;

tsl/test/sql/direct_compress_insert.sql

@@ -551,3 +551,21 @@ RESET timescaledb.enable_direct_compress_insert;
 DROP VIEW metrics_view_pos;
 DROP TABLE metrics_view;
 
+-- Direct compress must be disabled when the table has an exclusion constraint
+CREATE TABLE dc_excl(time timestamptz NOT NULL, device text NOT NULL, value float,
+    EXCLUDE USING btree (time WITH =, device WITH =))
+    WITH (tsdb.hypertable, tsdb.partition_column='time');
+ALTER TABLE dc_excl SET (timescaledb.compress, timescaledb.compress_segmentby='device');
+SET timescaledb.enable_direct_compress_insert = true;
+-- insert warns, disables direct compress and falls back to a normal insert
+INSERT INTO dc_excl SELECT '2025-01-01'::timestamptz + (i || ' minute')::interval, 'd1', i::float FROM generate_series(1,100) i;
+-- chunk stays uncompressed since direct compress was disabled
+SELECT DISTINCT _timescaledb_functions.chunk_status_text(chunk) FROM show_chunks('dc_excl') chunk;
+-- exclusion constraint is still enforced
+\set ON_ERROR_STOP 0
+INSERT INTO dc_excl VALUES ('2025-01-01'::timestamptz + INTERVAL '1 minute', 'd1', 99);
+\set ON_ERROR_STOP 1
+SELECT count(*) FROM dc_excl;
+RESET timescaledb.enable_direct_compress_insert;
+DROP TABLE dc_excl;
+