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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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31
src/backend/optimizer/path/joinpath.c
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@@ -394,9 +394,15 @@ paraminfo_get_equal_hashops(PlannerInfo *root, ParamPathInfo *param_info,
RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
OpExpr *opexpr;
Node *expr;
Oid hasheqoperator;
/* can't use a memoize node without a valid hash equals operator */
if (!OidIsValid(rinfo->hasheqoperator) ||
opexpr = (OpExpr *) rinfo->clause;
/*
* Bail if the rinfo is not compatible. We need a join OpExpr
* with 2 args.
*/
if (!IsA(opexpr, OpExpr) || list_length(opexpr->args) != 2 ||
!clause_sides_match_join(rinfo, outerrel, innerrel))
{
list_free(*operators);
@@ -404,17 +410,26 @@ paraminfo_get_equal_hashops(PlannerInfo *root, ParamPathInfo *param_info,
return false;
}
/*
* We already checked that this is an OpExpr with 2 args when
* setting hasheqoperator.
*/
opexpr = (OpExpr *) rinfo->clause;
if (rinfo->outer_is_left)
{
expr = (Node *) linitial(opexpr->args);
hasheqoperator = rinfo->left_hasheqoperator;
}
else
{
expr = (Node *) lsecond(opexpr->args);
hasheqoperator = rinfo->right_hasheqoperator;
}
*operators = lappend_oid(*operators, rinfo->hasheqoperator);
/* can't do memoize if we can't hash the outer type */
if (!OidIsValid(hasheqoperator))
{
list_free(*operators);
list_free(*param_exprs);
return false;
}
*operators = lappend_oid(*operators, hasheqoperator);
*param_exprs = lappend(*param_exprs, expr);
}
}