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Fix handling of clauses incompatible with extended statistics

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Handling of incompatible clauses while applying extended statistics was
a bit confused - while handling a mix of compatible and incompatible
clauses it sometimes incorrectly treated the incompatible clauses as
compatible, resulting in a crash.

Fixed by reworking the code applying the selected statistics object to
make it easier to understand, and adding a proper compatibility check.

Reported-by: David Rowley
Discussion: https://postgr.es/m/CAApHDvpYT10-nkSp8xXe-nbO3jmoaRyRFHbzh-RWMfAJynqgpQ%40mail.gmail.com
This commit is contained in:
Tomas Vondra
2021-04-06 16:12:37 +02:00
parent 7ab96cf6b3
commit 518442c7f3
4 changed files with 102 additions and 30 deletions
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4
src/backend/statistics/mcv.c
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@@ -1575,6 +1575,8 @@ mcv_match_expression(Node *expr, Bitmapset *keys, List *exprs, Oid *collid)
(idx <= bms_num_members(keys) + list_length(exprs)));
}
Assert((idx >= 0) && (idx < bms_num_members(keys) + list_length(exprs)));
return idx;
}
@@ -1654,6 +1656,8 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
/* match the attribute/expression to a dimension of the statistic */
idx = mcv_match_expression(clause_expr, keys, exprs, &collid);
Assert((idx >= 0) && (idx < bms_num_members(keys) + list_length(exprs)));
/*
* Walk through the MCV items and evaluate the current clause. We
* can skip items that were already ruled out, and terminate if