From: Tom Lane <tgl@sss.pgh.pa.us>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: When replanning a plpgsql "simple expression", check it's still
Date: Thu, 13 Jun 2024 17:38:13 +0000
Message-ID: <E1sHoOq-001Lqc-FY@gemulon.postgresql.org> (raw)
When replanning a plpgsql "simple expression", check it's still simple.
The previous coding here assumed that we didn't need to recheck any
of the querytree tests made in exec_simple_check_plan(). I think
we supposed that those properties were fully determined by the
syntax of the source text and hence couldn't change. That is true
for most of them, but at least hasTargetSRFs and hasAggs can change
by dint of forcibly dropping an originally-referenced function and
recreating it with new properties. That leads to "unexpected plan
node type" or similar failures.
These tests are pretty cheap compared to the cost of replanning, so
rather than sweat over exactly which properties need to be rechecked,
let's just recheck them all. Hence, factor out those tests into a new
function exec_is_simple_query(), and rearrange callers as needed.
A second problem in the same area was that if we failed during
replanning or during exec_save_simple_expr(), we'd potentially
leave behind now-dangling pointers to the old simple expression,
potentially resulting in crashes later. To fix, clear those pointers
before replanning.
The v12 code looks quite different in this area but still has the
bug about needing to recheck query simplicity. I chose to back-patch
all of the plpgsql_simple.sql test script, which formerly didn't exist
in this branch.
Per bug #18497 from Nikita Kalinin. Back-patch to all supported
branches.
Discussion: https://postgr.es/m/18497-fe93b6da82ce31d4@postgresql.org
Branch
------
REL_14_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/1450db793f643991e4684fa8b5cee6ded51ab870
Modified Files
--------------
src/pl/plpgsql/src/expected/plpgsql_simple.out | 29 +++++
src/pl/plpgsql/src/pl_exec.c | 143 +++++++++++++++----------
src/pl/plpgsql/src/sql/plpgsql_simple.sql | 22 ++++
3 files changed, 138 insertions(+), 56 deletions(-)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-committers@postgresql.org
Cc: tgl@sss.pgh.pa.us, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: When replanning a plpgsql "simple expression", check it's still
In-Reply-To: <E1sHoOq-001Lqc-FY@gemulon.postgresql.org>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox