From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
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To: | Gregory Stark <stark(at)enterprisedb(dot)com> |
Cc: | PostgreSQL-development Hackers <pgsql-patches(at)postgresql(dot)org> |
Subject: | Re: Buglet in "Sort Method" explain output in degenerate case |
Date: | 2007-09-01 18:19:53 |
Message-ID: | 22961.1188670793@sss.pgh.pa.us |
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Lists: | pgsql-patches |
Gregory Stark <stark(at)enterprisedb(dot)com> writes:
> It's printing "quicksort" even though it used a heap. This happens because we
> don't bother deheapifying a singleton heap so the boundUsed flag never gets
> set. The patch below just moves setting that flag to when the heap is made
> instead of when it's deheapified.
Hmm. Actually, given that sort_bounded_heap() is only conditionally
invoked, *both* of the state updates it makes are bogus. But I think
they should both be done at the call site in tuplesort_performsort.
(The state->status update already is, which is why it works at all.)
Setting it at conclusion is correct, I think, since if we ever changed
the code to abandon TSS_BOUNDED state in the face of unexpected memory
growth, it would be wrong to have set it in make_bounded_sort.
regards, tom lane
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