Support AQUMV exact-match for multi-table JOIN queries#1606
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avamingli wants to merge 2 commits intoapache:mainfrom
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Support AQUMV exact-match for multi-table JOIN queries#1606avamingli wants to merge 2 commits intoapache:mainfrom
avamingli wants to merge 2 commits intoapache:mainfrom
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This commit implements exact-match rewriting, step2 of Materialized views with JOINs when Answer Query? . |
yjhjstz
reviewed
Mar 6, 2026
Add a new AQUMV code path that rewrites multi-table JOIN queries to
scan materialized views when the query exactly matches the MV
definition. This compares the saved raw parse tree against stored
viewQuery from gp_matview_aux, bypassing the single-table AQUMV
logic entirely.
This enables significant query acceleration for common analytical
patterns: instead of repeatedly computing expensive multi-table joins
at query time, the planner can directly read pre-computed results
from the materialized view, turning O(N*M) join operations into a
simple sequential scan.
For example, given:
CREATE MATERIALIZED VIEW mv AS
SELECT t1.a, t2.b FROM t1 JOIN t2 ON t1.a = t2.a;
-- Before (GUC off): original join plan
Gather Motion 3:1
-> Hash Join
Hash Cond: (t1.a = t2.a)
-> Seq Scan on t1
-> Hash
-> Seq Scan on t2
-- After (GUC on): rewritten to MV scan
Gather Motion 3:1
-> Seq Scan on mv
yjhjstz
reviewed
Mar 9, 2026
| viewQuery->hasAggs = false; | ||
| viewQuery->groupClause = NIL; | ||
| viewQuery->havingQual = NULL; | ||
| viewQuery->sortClause = NIL; |
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sortClause is cleared. Since MV scans don't guarantee order, results may come back unsorted ？
yjhjstz
reviewed
Mar 9, 2026
src/backend/optimizer/plan/aqumv.c
Outdated
| * so a zeroed struct of that size works correctly (both fields NIL). | ||
| */ | ||
| { | ||
| char clean_qp_extra[2 * sizeof(List *)]; |
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clean_qp_extra hardcodes 2 * sizeof(List *) assuming the private standard_qp_extra struct layout. If that struct changes, query_planner reads garbage memory. Should expose the struct properly in a header？
yjhjstz
reviewed
Mar 9, 2026
| return false; | ||
| if (!equal(raw_parse->limitCount, viewQuery->limitCount)) | ||
| return false; | ||
| if (!equal(raw_parse->limitOffset, viewQuery->limitOffset)) |
yjhjstz
reviewed
Mar 9, 2026
| } | ||
|
|
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| /* Compare GROUP BY, HAVING, ORDER BY, DISTINCT, LIMIT */ | ||
| if (!equal(raw_parse->groupClause, viewQuery->groupClause)) |
Fix three issues in aqumv_query_is_exact_match(): - Add groupDistinct comparison (GROUP BY vs GROUP BY DISTINCT) - Add limitOption comparison (LIMIT vs FETCH FIRST WITH TIES) - Clear qp_extra in-place via aqumv_context->qp_extra instead of allocating a local char array; move standard_qp_extra typedef to planner.h so aqumv.c can reference the proper struct type Add test cases 26-28 to verify the new comparisons: - LIMIT vs FETCH FIRST WITH TIES non-match and exact match - GROUP BY DISTINCT vs GROUP BY non-match
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Add a new AQUMV code path that rewrites multi-table JOIN queries to scan materialized views when the query exactly matches the MV definition. This compares the saved raw parse tree against stored viewQuery from gp_matview_aux, bypassing the single-table AQUMV logic entirely.
This enables significant query acceleration for common analytical patterns: instead of repeatedly computing expensive multi-table joins at query time, the planner can directly read pre-computed results from the materialized view, turning O(N*M) join operations into a simple sequential scan.
For example, given:
Fixes #ISSUE_Number
What does this PR do?
Type of Change
Breaking Changes
Test Plan
make installcheckmake -C src/test installcheck-cbdb-parallelImpact
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User-facing changes:
Dependencies:
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