Thread

Re: Fix unsafe PlannedStmt access in pg_stat_statements

Andres Freund <andres@anarazel.de> — 2026-05-12T09:00:16Z

Hi, 

On May 12, 2026 5:30:53 AM GMT+02:00, Michael Paquier <michael@paquier.xyz> wrote:
>On Mon, May 11, 2026 at 04:11:41PM +0800, Chao Li wrote:
>> On May 11, 2026, at 16:07, Chao Li <li.evan.chao@gmail.com> wrote:
>>> In pgss_ProcessUtility(), there is this comment:
>>> ```
>>> /*
>>> * CAUTION: do not access the *pstmt data structure again below here.
>>> * If it was a ROLLBACK or similar, that data structure may have been
>>> * freed.  We must copy everything we still need into local variables,
>>> * which we did above.
>>> *
>>> * For the same reason, we can't risk restoring pstmt->queryId to its
>>> * former value, which'd otherwise be a good idea.
>>> */
>>> ```
>>> 
>>> The attached patch fixes this by saving pstmt->planOrigin,
>>> following the same pattern already used for queryId, stmt_location,
>>> and stmt_len.
>
>Yeah, you are right.  This code should save the planOrigin but it does
>not do so.

Seems like the code should make this clearer, by simply unsetting pstmt at the point it becomes unsafe to use? 


Andres