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Transform OR clauses to ANY expression

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Replace (expr op C1) OR (expr op C2) ... with expr op ANY(ARRAY[C1, C2, ...])
on the preliminary stage of optimization when we are still working with the
expression tree.

Here Cn is a n-th constant expression, 'expr' is non-constant expression, 'op'
is an operator which returns boolean result and has a commuter (for the case
of reverse order of constant and non-constant parts of the expression,
like 'Cn op expr').

Sometimes it can lead to not optimal plan.  This is why there is a
or_to_any_transform_limit GUC.  It specifies a threshold value of length of
arguments in an OR expression that triggers the OR-to-ANY transformation.
Generally, more groupable OR arguments mean that transformation will be more
likely to win than to lose.

Discussion: https://postgr.es/m/567ED6CA.2040504%40sigaev.ru
Author: Alena Rybakina <lena.ribackina@yandex.ru>
Author: Andrey Lepikhov <a.lepikhov@postgrespro.ru>
Reviewed-by: Peter Geoghegan <pg@bowt.ie>
Reviewed-by: Ranier Vilela <ranier.vf@gmail.com>
Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Jian He <jian.universality@gmail.com>
This commit is contained in:
Alexander Korotkov
2024-04-08 01:27:28 +03:00
parent 75a47b6a0d
commit 72bd38cc99
14 changed files with 785 additions and 20 deletions
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27
src/backend/nodes/queryjumblefuncs.c
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@@ -141,6 +141,33 @@ JumbleQuery(Query *query)
return jstate;
}
JumbleState *
JumbleExpr(Expr *expr, uint64 *exprId)
{
JumbleState *jstate = NULL;
Assert(exprId != NULL);
jstate = (JumbleState *) palloc(sizeof(JumbleState));
/* Set up workspace for query jumbling */
jstate->jumble = (unsigned char *) palloc(JUMBLE_SIZE);
jstate->jumble_len = 0;
jstate->clocations_buf_size = 32;
jstate->clocations = (LocationLen *)
palloc(jstate->clocations_buf_size * sizeof(LocationLen));
jstate->clocations_count = 0;
jstate->highest_extern_param_id = 0;
/* Compute query ID */
_jumbleNode(jstate, (Node *) expr);
*exprId = DatumGetUInt64(hash_any_extended(jstate->jumble,
jstate->jumble_len,
0));
return jstate;
}
/*
* Enables query identifier computation.
*