On Fri, Sep 5, 2014 at 3:09 PM, Robert Haas <robertmh...@gmail.com> wrote: > On Fri, Sep 5, 2014 at 4:17 AM, didier <did...@gmail.com> wrote: >>> It's not the size of the array that's the problem; it's the size of >>> the detonation when the allocation fails. >>> >> You can use a file backed memory array >> Or because it's only a hint and >> - keys are in buffers (BufferTag), right? >> - transition is only from 'data I care to data I don't care' if a >> buffer is concurrently evicted when sorting. >> >> Use a pre allocate buffer index array an read keys from buffers when >> sorting, without memory barrier, spinlocks, whatever. > > If by a file-backed memory array you mean mmap() something, that > doesn't do anything to address the possibility of failure. mmap(), > like malloc(), can fail.
It's worse. If your process needs to page from disk when touching a byte in the mmap'd array, and the disk somehow fails to work, you get a segmentation fault. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
