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Fix incorrect hash equality operator bug in Memoize

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In v14, because we don't have a field in RestrictInfo to cache both the
left and right type's hash equality operator, we just restrict the scope
of Memoize to only when the left and right types of a RestrictInfo are the
same.

In master we add another field to RestrictInfo and cache both hash
equality operators.

Reported-by: Jaime Casanova
Author: David Rowley
Discussion: https://postgr.es/m/20210929185544.GB24346%40ahch-to
Backpatch-through: 14
This commit is contained in:
David Rowley
2021-11-08 14:40:33 +13:00
parent e2fbb88372
commit 39a3105678
6 changed files with 54 additions and 22 deletions
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28
src/backend/optimizer/plan/initsplan.c
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@ -2711,15 +2711,16 @@ check_hashjoinable(RestrictInfo *restrictinfo)
/*
* check_memoizable
* If the restrictinfo's clause is suitable to be used for a Memoize node,
* set the hasheqoperator to the hash equality operator that will be needed
* during caching.
* set the lefthasheqoperator and righthasheqoperator to the hash equality
* operator that will be needed during caching.
*/
static void
check_memoizable(RestrictInfo *restrictinfo)
{
TypeCacheEntry *typentry;
Expr *clause = restrictinfo->clause;
Node *leftarg;
Oid lefttype;
Oid righttype;
if (restrictinfo->pseudoconstant)
return;
@ -2728,13 +2729,24 @@ check_memoizable(RestrictInfo *restrictinfo)
if (list_length(((OpExpr *) clause)->args) != 2)
return;
leftarg = linitial(((OpExpr *) clause)->args);
lefttype = exprType(linitial(((OpExpr *) clause)->args));
typentry = lookup_type_cache(exprType(leftarg), TYPECACHE_HASH_PROC |
typentry = lookup_type_cache(lefttype, TYPECACHE_HASH_PROC |
TYPECACHE_EQ_OPR);
if (!OidIsValid(typentry->hash_proc) || !OidIsValid(typentry->eq_opr))
return;
if (OidIsValid(typentry->hash_proc) && OidIsValid(typentry->eq_opr))
restrictinfo->left_hasheqoperator = typentry->eq_opr;
restrictinfo->hasheqoperator = typentry->eq_opr;
righttype = exprType(lsecond(((OpExpr *) clause)->args));
/*
* Lookup the right type, unless it's the same as the left type, in which
* case typentry is already pointing to the required TypeCacheEntry.
*/
if (lefttype != righttype)
typentry = lookup_type_cache(righttype, TYPECACHE_HASH_PROC |
TYPECACHE_EQ_OPR);
if (OidIsValid(typentry->hash_proc) && OidIsValid(typentry->eq_opr))
restrictinfo->right_hasheqoperator = typentry->eq_opr;
}