Re: [BUGS] vacuum analyze corrupts db with larger tuples (< 8k) - Mailing list pgsql-bugs

I wrote:
> Ohhh ... I know what's going on.  The oversize tuple is the one that
> VACUUM is attempting to store in pg_statistic, containing the min and
> max values for your varchar column.  In this example, both the min and
> max are just shy of 5K characters, so the pg_statistic tuple is too
> big to fit on a page.

I have applied the attached patch to the REL6_5 branch.  (There is
already similar code in the current branch.)  I'm afraid it won't
help you recover from an already-corrupted pg_statistic table, though.

            regards, tom lane

*** src/backend/commands/vacuum.c.orig    Wed Aug 25 08:01:45 1999
--- src/backend/commands/vacuum.c    Tue Jan  4 12:15:17 2000
***************
*** 2405,2414 ****
                      stup = heap_formtuple(sd->rd_att, values, nulls);

                      /* ----------------
!                      *    insert the tuple in the relation and get the tuple's oid.
                       * ----------------
                       */
!                     heap_insert(sd, stup);
                      pfree(DatumGetPointer(values[3]));
                      pfree(DatumGetPointer(values[4]));
                      pfree(stup);
--- 2405,2425 ----
                      stup = heap_formtuple(sd->rd_att, values, nulls);

                      /* ----------------
!                      *    Watch out for oversize tuple, which can happen if
!                      *    both of the saved data values are long.
!                      *    Our fallback strategy is just to not store the
!                      *    pg_statistic tuple at all in that case.  (We could
!                      *    replace the values by NULLs and still store the
!                      *    numeric stats, but presently selfuncs.c couldn't
!                      *    do anything useful with that case anyway.)
                       * ----------------
                       */
!                     if (MAXALIGN(stup->t_len) <= MaxTupleSize)
!                     {
!                         /* OK to store tuple */
!                         heap_insert(sd, stup);
!                     }
!
                      pfree(DatumGetPointer(values[3]));
                      pfree(DatumGetPointer(values[4]));
                      pfree(stup);