Re: The return value of allocate_recordbuf()

On Thu, Feb 12, 2015 at 04:02:52PM +0900, Michael Paquier wrote:
> Yes, why not using palloc_extended instead of palloc_noerror that has been
> clearly rejected in the other thread. Now, for palloc_extended we should copy
> the flags of MemoryContextAllocExtended to fe_memutils.h and have the same
> interface between frontend and backend (note that MCXT_ALLOC_HUGE has no real
> utility for frontends). Attached is a patch to achieve that, completed with a
> second patch for the problem related to this thread. Note that in the second
> patch I have added an ERROR in logical.c after calling XLogReaderAllocate, this
> was missing..
>
>
> > Btw, the huge flag should be used as well as palloc only allows
> > allocation up to 1GB, and this is incompatible with ~9.4 where malloc
> > is used.
>
> I think that flag should be used only if it's needed, not just on the
> grounds that 9.4 has no such limit. In general, limiting allocations
> to 1GB has been good to us; for example, it prevents a corrupted TOAST
> length from causing a memory allocation large enough to crash the
> machine (yes, there are machines you can crash with a giant memory
> allocation!). We should bypass that limit only where it is clearly
> necessary.
>
>
> Fine for me to error out in this code path if we try more than 1GB of
> allocation.

Where are we on this?

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

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