From 1b1106cace29025ef96b364e5bcd5bc7930c2eb7 Mon Sep 17 00:00:00 2001 From: Alvaro Herrera Date: Wed, 21 Apr 2021 15:42:03 -0400 Subject: [PATCH 2/2] Make partitions-omitted partdescs have stmt lifetime --- src/backend/partitioning/partdesc.c | 50 ++++++++++++++++++++--------- 1 file changed, 35 insertions(+), 15 deletions(-) diff --git a/src/backend/partitioning/partdesc.c b/src/backend/partitioning/partdesc.c index 7d019a72be..399390b42c 100644 --- a/src/backend/partitioning/partdesc.c +++ b/src/backend/partitioning/partdesc.c @@ -88,6 +88,12 @@ RelationGetPartitionDesc(Relation rel, bool include_detached) * context the current context except in very brief code sections, out of fear * that some of our callees allocate memory on their own which would be leaked * permanently. + * + * As a special case, partition descriptors that are requested to omit + * partitions being detached (and which contain such partitions) are transient + * and are not to be associated with the relcache entry. Such descriptors only + * last through the requesting Portal, so we use the corresponding memory + * context for them. */ static PartitionDesc RelationBuildPartitionDesc(Relation rel, bool include_detached) @@ -262,25 +268,39 @@ RelationBuildPartitionDesc(Relation rel, bool include_detached) } /* - * We have a fully valid partdesc ready to store into the relcache. - * Reparent it so it has the right lifespan. + * We have a fully valid partdesc. Reparent it so that it has the right + * lifespan, and if appropriate put it into the relation's relcache entry. */ - MemoryContextSetParent(new_pdcxt, CacheMemoryContext); + if (!include_detached && detached_exist) + { + /* + * A transient partition descriptor is only good for the current + * statement, so make it a child of the current portal's context. + */ + MemoryContextSetParent(new_pdcxt, PortalContext); + } + else + { + /* + * This partdesc goes into relcache. + */ - /* - * But first, a kluge: if there's an old rd_pdcxt, it contains an old - * partition descriptor that may still be referenced somewhere. Preserve - * it, while not leaking it, by reattaching it as a child context of the - * new rd_pdcxt. Eventually it will get dropped by either RelationClose - * or RelationClearRelation. - */ - if (rel->rd_pdcxt != NULL) - MemoryContextSetParent(rel->rd_pdcxt, new_pdcxt); - rel->rd_pdcxt = new_pdcxt; + MemoryContextSetParent(new_pdcxt, CacheMemoryContext); - /* Store it into relcache, but only if no detached partitions exist */ - if (!detached_exist) + /* + * But first, a kluge: if there's an old rd_pdcxt, it contains an old + * partition descriptor that may still be referenced somewhere. + * Preserve it, while not leaking it, by reattaching it as a child + * context of the new rd_pdcxt. Eventually it will get dropped by + * either RelationClose or RelationClearRelation. + */ + if (rel->rd_pdcxt != NULL) + MemoryContextSetParent(rel->rd_pdcxt, new_pdcxt); + rel->rd_pdcxt = new_pdcxt; + + /* Store it into relcache */ rel->rd_partdesc = partdesc; + } return partdesc; } -- 2.20.1