Re: Segmentation fault on PG 8.4 CVS head

Tom fixed this upstream, and I just merged with PostgreSQL CVS HEAD
again. The buildfarm crash should now be fixed.

Rushabh Lathia wrote:
> Hi All,
>
> While running test with bind varible getting segmentation fault. ( CVS Head
> 8.4)
>
> For testcase, please find the crash.c (C test) and test.java ( JDBC test)
> attached with the mail.
>
> Had a quick look at the core dump and found the call stack for the
> segmentation fault.
>
> (gdb) bt
> #0 0x0813768d in analyze_requires_snapshot (parseTree=0x0) at analyze.c:270
>
> #1 0x082e77a8 in exec_bind_message (input_message=0xbfd7d73c) at
> postgres.c:1698
> #2 0x082ec524 in PostgresMain (argc=4, argv=0x916fc70, username=0x916fb7c
> "rushabh") at postgres.c:4882
> #3 0x082ac10a in BackendRun (port=0x9191b18) at postmaster.c:3309
> #4 0x082ab4d4 in BackendStartup (port=0x9191b18) at postmaster.c:2881
> #5 0x082a8ae1 in ServerLoop () at postmaster.c:1291
>
> Had a look at the previous version and found that because of following
> condition added with the new PG merge into exec_bind_message(); we end up
> with the segmentation fault.
>
> exec_bind_message{
> ...
> /*
> * Set a snapshot if we have parameters to fetch (since the input
> * functions might need it) or the query isn't a utility command (and
> * hence could require redoing parse analysis and planning).
> */
> if (numParams > 0 || analyze_requires_snapshot(psrc->raw_parse_tree))
> {
> PushActiveSnapshot(GetTransactionSnapshot());
> snapshot_set = true;
> }
> ...
> }
>
>
> Condition added with "Fix failure to ensure that a snapshot is available to
> datatype input functions" commit. (
> http://git.postgresql.org/?p=postgresql.git;a=commitdiff;h=d5e7e5dd7c81440bb46f52872906633ee2b388c1
> )
>
> Not very much sure but for the quick check I just modifiled condition by
> added check for raw_parse_tree and test worked file.
>
> Modified condition:
> /*
> * Set a snapshot if we have parameters to fetch (since the input
> * functions might need it) or the query isn't a utility command (and
> * hence could require redoing parse analysis and planning).
> */
> if (numParams > 0 ||
> (psrc->raw_parse_tree &&
> analyze_requires_snapshot(psrc->raw_parse_tree)))
> {
> PushActiveSnapshot(GetTransactionSnapshot());
> snapshot_set = true;
> }
>
> Another fix would be to add check for parseTree into
> analyze_requires_snapshot().
>
> Thanks ,
> Rushabh Lathia
> www.EnterpriseDB.com
>
>
>
> ------------------------------------------------------------------------
>
>

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com