Re: pg_stat_statements: Fix nested tracking for implicitly closed cursors

From: Michael Paquier <michael(at)paquier(dot)xyz>
To: Sami Imseih <samimseih(at)gmail(dot)com>
Cc: Martin Huang <jjja5555(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: pg_stat_statements: Fix nested tracking for implicitly closed cursors
Date: 2026-01-16 22:12:48
Message-ID: aWq34FtyC6Y4pdig@paquier.xyz
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On Tue, Jan 13, 2026 at 07:01:48PM -0600, Sami Imseih wrote:
> Correct.Thanks for spotting this oversight. I think the is_txn_end flag must
> be reset in all hook functions that call pgss_store, except in pgss_ExecutorEnd,
> where we just have to check is_txn_end and increment the nesting_level. Also,
> I added a PG_TRY/FINALLY inside pgss_ExecutorEnd to ensure we reset the
> nesting_level is reset.
>
> I added a test case for the query you mentioned above.

@@ -1079,35 +1095,47 @@ pgss_ExecutorEnd(QueryDesc *queryDesc)
{
int64 queryId = queryDesc->plannedstmt->queryId;

- if (queryId != INT64CONST(0) && queryDesc->totaltime &&
- pgss_enabled(nesting_level))
+ if (is_txn_end)
+ nesting_level++;

Couldn't it be possible that we reach this stack of execution with
is_txn_end = true but we don't intend it to be so? For example,
imagine first that we reach pgss_ProcessUtility() for a COMMIT
TransactionStmt, second we error without resetting is_txn_end, third a
different portal is executed a with the same backend: we could exit
the executor with is_txn_end set and nesting_level increased but we
did not intend these events to happen.
--
Michael

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