From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | James Coleman <jtc331(at)gmail(dot)com> |
Cc: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Misleading comment in tuplesort_set_bound |
Date: | 2019-08-26 21:51:21 |
Message-ID: | 25719.1566856281@sss.pgh.pa.us |
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Lists: | pgsql-hackers |
James Coleman <jtc331(at)gmail(dot)com> writes:
> While digging into the incremental sort patch, I noticed in
> tuplesort.c at the beginning of the function in $SUBJECT we have this
> comment and assertion:
> tuplesort_set_bound(Tuplesortstate *state, int64 bound)
> {
> /* Assert we're called before loading any tuples */
> Assert(state->status == TSS_INITIAL);
> But AFAICT from reading the code in puttuple_common the state remains
> TSS_INITIAL while tuples are inserted (unless we reach a point where
> we decide to transition it to TSS_BOUNDED or TSS_BUILDRUNS).
You missed the relevance of the next line:
Assert(state->memtupcount == 0);
I think the comment is fine as-is. Perhaps the code would be clearer
though, if we merged those two asserts into one?
/* Assert we're called before loading any tuples */
Assert(state->status == TSS_INITIAL &&
state->memtupcount == 0);
I'm not totally sure about the usefulness/relevance of the two
assertions following these, but they could likely do with their
own comment(s), because this one surely isn't covering them.
regards, tom lane
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