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svenklemmsvenklemm
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Add DeferredChunkScan custom scan
Add a new custom scan node for LIMIT queries that leaves the hypertable unexpanded during initial planning and defers chunk enumeration and scanning to execution time. This gives huge speedup to LIMIT queries on hypertables with many chunks. Warm planning time (ms), median of 15, ORDER BY ts LIMIT 1 ┌────────────────────────────┬───────┬───────┬───────┬───────┬───────┬───────┬────────┐ │ config │ 1 │ 10 │ 50 │ 100 │ 1,000 │ 5,000 │ 10,000 │ ├────────────────────────────┼───────┼───────┼───────┼───────┼───────┼───────┼────────┤ │ uncompr, expanded │ 0.010 │ 0.037 │ 0.173 │ 0.372 │ 4.39 │ 35.9 │ 84.3 │ ├────────────────────────────┼───────┼───────┼───────┼───────┼───────┼───────┼────────┤ │ uncompr, DeferredChunkScan │ 0.003 │ 0.003 │ 0.003 │ 0.002 │ 0.002 │ 0.002 │ 0.002 │ ├────────────────────────────┼───────┼───────┼───────┼───────┼───────┼───────┼────────┤ │ compr, expanded │ 0.019 │ 0.136 │ 0.636 │ 1.361 │ 27.1 │ 169.9 │ 363.1 │ ├────────────────────────────┼───────┼───────┼───────┼───────┼───────┼───────┼────────┤ │ compr, DeferredChunkScan │ 0.003 │ 0.003 │ 0.003 │ 0.002 │ 0.002 │ 0.003 │ 0.003 │ └────────────────────────────┴───────┴───────┴───────┴───────┴───────┴───────┴────────┘ Warm execution time (ms), median of 15, ORDER BY ts LIMIT 1 ┌────────────────────────────┬───────┬───────┬───────┬───────┬────────┬───────┬────────┐ │ config │ 1 │ 10 │ 50 │ 100 │ 1,000 │ 5,000 │ 10,000 │ ├────────────────────────────┼───────┼───────┼───────┼───────┼────────┼───────┼────────┤ │ uncompr, expanded │ 0.002 │ 0.005 │ 0.015 │ 0.093 │ 0.88 │ 9.97 │ 23.6 │ ├────────────────────────────┼───────┼───────┼───────┼───────┼────────┼───────┼────────┤ │ uncompr, DeferredChunkScan │ 0.021 │ 0.022 │ 0.018 │ 0.017 │ 0.018 │ 0.017 │ 0.018 │ ├────────────────────────────┼───────┼───────┼───────┼───────┼────────┼───────┼────────┤ │ compr, expanded │ 0.004 │ 0.015 │ 0.143 │ 0.301 │ 6.33 │ 42.4 │ 92.3 │ ├────────────────────────────┼───────┼───────┼───────┼───────┼────────┼───────┼────────┤ │ compr, DeferredChunkScan │ 0.037 │ 0.037 │ 0.029 │ 0.029 │ 6.1e-2 │ 0.030 │ 0.031 │ └────────────────────────────┴───────┴───────┴───────┴───────┴────────┴───────┴────────┘
1 parent c9baf4b commit e49575b

13 files changed

Lines changed: 2450 additions & 3 deletions

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‎src/guc.c‎

Lines changed: 31 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -95,6 +95,7 @@ bool ts_guc_enable_parallel_chunk_append = true;
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bool ts_guc_enable_runtime_exclusion = true;
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bool ts_guc_enable_constraint_exclusion = true;
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bool ts_guc_enable_hypertable_expansion_for_dml = true;
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TSDLLEXPORT bool ts_guc_enable_deferredchunkscan = false;
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bool ts_guc_enable_qual_propagation = true;
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TSDLLEXPORT bool ts_guc_enable_columnar_scan_filter_pushdown = true;
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bool ts_guc_enable_qual_filtering = true;
@@ -211,6 +212,8 @@ bool ts_guc_debug_have_int128;
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DebugRequireOption ts_guc_debug_require_vector_qual = DRO_Allow;
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DebugRequireOption ts_guc_debug_require_vector_agg = DRO_Allow;
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DebugRequireOption ts_guc_debug_require_deferred_chunk_scan = DRO_Allow;
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#endif
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DebugRequireOption ts_guc_debug_require_batch_sorted_merge = DRO_Allow;
@@ -778,6 +781,18 @@ _guc_init(void)
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NULL,
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NULL);
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DefineCustomBoolVariable(MAKE_EXTOPTION("enable_deferredchunkscan"),
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"Enable DeferredChunkScan for LIMIT queries",
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"Custom scan node for hypertables that iterates chunks at"
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"execution instead of expanding every chunk at plan time.",
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&ts_guc_enable_deferredchunkscan,
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false,
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PGC_USERSET,
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0,
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NULL,
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NULL,
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NULL);
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DefineCustomBoolVariable(MAKE_EXTOPTION("enable_foreign_key_propagation"),
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"Enable foreign key propagation",
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"Adjust foreign key lookup queries to target whole hypertable",
@@ -1711,6 +1726,22 @@ _guc_init(void)
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/* assign_hook= */ NULL,
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/* show_hook= */ NULL);
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DefineCustomEnumVariable(/* name= */ MAKE_EXTOPTION("debug_require_deferred_chunk_scan"),
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/* short_desc= */
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"ensure that DeferredChunkScan is used or not",
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/* long_desc= */
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"this is for debugging purposes, to check whether a query uses the "
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"DeferredChunkScan node without depending on version-specific EXPLAIN "
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"output",
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/* valueAddr= */ (int *) &ts_guc_debug_require_deferred_chunk_scan,
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/* bootValue= */ DRO_Allow,
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/* options = */ debug_require_options,
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/* context= */ PGC_USERSET,
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/* flags= */ 0,
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/* check_hook= */ NULL,
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/* assign_hook= */ NULL,
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/* show_hook= */ NULL);
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#endif
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/* register feature flags */

‎src/guc.h‎

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Original file line numberDiff line numberDiff line change
@@ -28,6 +28,7 @@ extern bool ts_guc_enable_qual_filtering;
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extern bool ts_guc_enable_runtime_exclusion;
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extern bool ts_guc_enable_constraint_exclusion;
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extern bool ts_guc_enable_hypertable_expansion_for_dml;
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extern TSDLLEXPORT bool ts_guc_enable_deferredchunkscan;
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extern bool ts_guc_enable_cagg_reorder_groupby;
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extern TSDLLEXPORT bool ts_guc_enable_cagg_window_functions;
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extern TSDLLEXPORT bool ts_guc_skip_cagg_invalidation;
@@ -150,6 +151,8 @@ extern TSDLLEXPORT DebugRequireOption ts_guc_debug_require_vector_qual;
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extern TSDLLEXPORT DebugRequireOption ts_guc_debug_require_vector_agg;
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extern TSDLLEXPORT DebugRequireOption ts_guc_debug_require_deferred_chunk_scan;
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#endif
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extern TSDLLEXPORT bool ts_guc_debug_compression_path_info;

‎src/init.c‎

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Original file line numberDiff line numberDiff line change
@@ -57,6 +57,7 @@ extern void _conn_mock_fini();
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#endif
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extern void _chunk_append_init();
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extern void _deferred_chunk_scan_init(void);
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TS_FUNCTION_INFO_V1(ts_post_load_init);
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@@ -111,6 +112,7 @@ _PG_init(void)
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_planner_init();
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_constraint_aware_append_init();
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_chunk_append_init();
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_deferred_chunk_scan_init();
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_event_trigger_init();
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_process_utility_init();
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_guc_init();

‎src/nodes/CMakeLists.txt‎

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Original file line numberDiff line numberDiff line change
@@ -3,3 +3,4 @@ set(SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/modify_hypertable.c
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target_sources(${PROJECT_NAME} PRIVATE ${SOURCES})
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add_subdirectory(chunk_append)
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add_subdirectory(constraint_aware_append)
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add_subdirectory(deferred_chunk_scan)

‎src/nodes/deferred_chunk_scan/CMakeLists.txt‎

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@@ -0,0 +1,2 @@
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set(SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/deferred_chunk_scan.c)
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target_sources(${PROJECT_NAME} PRIVATE ${SOURCES})

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