Re: Segmentation fault on PG 8.4 CVS head - Mailing list pgsql-hackers

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