From d7602f0731a3c5cac59cf2fc81bc336f800cb11a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Yhuel?= Date: Mon, 24 Oct 2022 16:33:26 +0200 Subject: [PATCH] minor optimization for ineq_histogram_selectivity() Avoid calling of get_actual_variable_range() when possible. With this change, 'probe' can still reach sslot.nvalues - 1 if needed, so the algorithm still works correctly. But if the right end of the hitogram bin is equal to sslot.values[sslot.nvalues - 2], 'probe' will stay strictly less than sslot.nvalues - 1 in the while loop, and we save a call to get_actual_variable_range(). Use of get_actual_variable_range() can sometimes lead to surprising slow planning time (see [1] and [2]) [1] https://www.postgresql.org/message-id/flat/CAECtzeVPM4Oi6dTdqVQmjoLkDBVChNj7ed3hNs1RGrBbwCJ7Cw%40mail.gmail.com [2] https://www.postgresql.org/message-id/flat/36adf760-680b-7a4a-e019-64f4eaaf6ff7%40gmail.com --- src/backend/utils/adt/selfuncs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c index 69e0fb98f5..c1bc67705c 100644 --- a/src/backend/utils/adt/selfuncs.c +++ b/src/backend/utils/adt/selfuncs.c @@ -1108,7 +1108,7 @@ ineq_histogram_selectivity(PlannerInfo *root, while (lobound < hibound) { - int probe = (lobound + hibound) / 2; + int probe = (lobound + hibound - 1) / 2; bool ltcmp; /* -- 2.30.2