Re: [HACKERS] alter_table.sql

Patrick Welche <prlw1(at)newn(dot)cam(dot)ac(dot)uk> writes:
> Story so far: I have a table called "found". vacuum() in
> src/backend/commands/vacuum.c gets called with vacrel="found". During
> vc_init() at line 177, vacrel is cleared (="").

What the ???

Somebody broke this code badly since I last looked at it. The vacuum
initialization sequence has been rearranged so that it does not work:
there is a CommitTransactionCommand call that occurs before the vacuum
parameters have been copied into safe-across-transactions storage.
We are reading already-freed memory at line 186.

Will fix ASAP.

BTW, this also demonstrates that the CLOBBER_FREED_MEMORY testing hack
I put into aset.c needs more work; it ought to clobber implicitly-freed
memory as well as explicitly pfree'd blocks. Had I done that I would
probably have seen a regression test failure from this bug. Will add
some more clobbering code and see what else breaks ;-)

regards, tom lane