Horton

Flush Memoize cache when non-key parameters change

David Rowley <drowley@postgresql.org>

View on postgr.es
Commit: 1050048a315790a505465bfcceb26eaf8dbc7e2e
Author: David Rowley <drowley@postgresql.org>
Date: 2021-11-24T01:56:18Z
Releases: 15.0 
Flush Memoize cache when non-key parameters change

It's possible that a subplan below a Memoize node contains a parameter
from above the Memoize node.  If this parameter changes then cache entries
may become out-dated due to the new parameter value.

Previously Memoize was mistakenly not aware of this.  We fix this here by
flushing the cache whenever a parameter that's not part of the cache
key changes.

Bug: #17213
Reported by: Elvis Pranskevichus
Author: David Rowley
Discussion: https://postgr.es/m/17213-988ed34b225a2862@postgresql.org
Backpatch-through: 14, where Memoize was added

Files

PathChange+/−
src/backend/executor/nodeMemoize.c modified +38 −0
src/backend/nodes/bitmapset.c modified +2 −0
src/backend/optimizer/plan/createplan.c modified +7 −3
src/backend/optimizer/util/clauses.c modified +31 −0
src/include/nodes/execnodes.h modified +2 −0
src/include/nodes/plannodes.h modified +1 −0
src/include/optimizer/clauses.h modified +2 −0
src/test/regress/expected/memoize.out modified +39 −0
src/test/regress/sql/memoize.sql modified +20 −0

Discussion