From: Amit Langote <amitlan@postgresql.org>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: SQL/JSON: Avoid initializing unnecessary ON ERROR / ON EMPTY ste
Date: Fri, 06 Sep 2024 03:07:14 +0000
Message-ID: <E1smPJZ-000LNj-8Q@gemulon.postgresql.org> (raw)
SQL/JSON: Avoid initializing unnecessary ON ERROR / ON EMPTY steps
When the ON ERROR / ON EMPTY behavior is to return NULL, returning
NULL directly from ExecEvalJsonExprPath() suffices. Therefore, there's
no need to create separate steps to check the error/empty flag or
those to evaluate the the constant NULL expression. This speeds up
common cases because the default ON ERROR / ON EMPTY behavior for
JSON_QUERY() and JSON_VALUE() is to return NULL. However, these steps
are necessary if the RETURNING type is a domain, as constraints on the
domain may need to be checked.
Reported-by: Jian He <jian.universality@gmail.com>
Author: Jian He <jian.universality@gmail.com>
Author: Amit Langote <amitlangote09@gmail.com>
Discussion: https://postgr.es/m/CACJufxEo4sUjKCYtda0_qt9tazqqKPmF1cqhW9KBOUeJFqQd2g@mail.gmail.com
Backpatch-through: 17
Branch
------
REL_17_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/e4e27976a687dd641c1c8251fad3a90a08756df8
Modified Files
--------------
src/backend/executor/execExpr.c | 30 ++++++++++++++++++++++--------
1 file changed, 22 insertions(+), 8 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: amitlan@postgresql.org, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: SQL/JSON: Avoid initializing unnecessary ON ERROR / ON EMPTY ste
In-Reply-To: <E1smPJZ-000LNj-8Q@gemulon.postgresql.org>
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