Re: backend crash with certain statements/tables

Jeff Bohmer <bohmer@visionlink.org> writes:
> Running any of these statements on my database causes the backend to
> crash (example from PG log below):

Crash confirmed here.  Seems to be a side-effect of the 7.4 optimization
that tries to avoid "unnecessary" projection steps.  In the "SELECT *
FROM foo LIMIT" case, the scan plan decides it need not do projection,
but actually one must occur (else heap_insert will scribble on the
source table :-().  The junkfilter code in execMain.c is supposed to
catch this situation, but it's fooled by the presence of a LIMIT step.
There may be some related cases, need to think more.

I should have a patch later today.

            regards, tom lane