Horton

Re: BUG #14722: Segfault in tuplesort_heap_siftup, 32 bit overflow

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Sergey Koposov <skoposov@cmu.edu>
Cc: "pgsql-bugs@postgresql.org" <pgsql-bugs@postgresql.org>
Date: 2017-06-29T18:10:13Z
Lists: pgsql-bugs 
On Thu, Jun 29, 2017 at 10:50 AM, Sergey Koposov <skoposov@cmu.edu> wrote:
> For the time being I've just changed the type of i,j from int to long
> (or int64) and I am running the index creation now. I let you submit a
> patch -- thanks in advance.

That's more or less what I had in mind.

>  I also noticed that the availMem variable was negative in the printout
> of the TupleSortState.
>  availMem =-6442450776,
> I don't know whether that's an issue on its own or was caused by the
> (i,j) overflow. (availMem seems to be int64 variable though).

That's definitely allowed to go negative, which is why it's int64.
That's about 6GB of memory, though, which seems unusually large.

-- 
Peter Geoghegan

Commits

  1. Avoid integer overflow while sifting-up a heap in tuplesort.c.

  2. Implement binary heap replace-top operation in a smarter way.

  3. Permit super-MaxAllocSize allocations with MemoryContextAllocHuge().