Re: [HACKERS] Missing CHECK_FOR_INTERRUPTS in hash joins - Mailing list pgsql-hackers

From Tom Lane
Subject Re: [HACKERS] Missing CHECK_FOR_INTERRUPTS in hash joins
Date
Msg-id 6969.1487192586@sss.pgh.pa.us
Whole thread Raw
In response to Re: [HACKERS] Missing CHECK_FOR_INTERRUPTS in hash joins  (Thomas Munro <thomas.munro@enterprisedb.com>)
List pgsql-hackers
Thomas Munro <thomas.munro@enterprisedb.com> writes:
> On Wed, Feb 15, 2017 at 2:22 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Adding a C.F.I. inside this loop is the most straightforward fix, but
>> I am leaning towards adding one in ExecHashJoinGetSavedTuple instead,

> Would it also make sense to put one in the loop in
> ExecHashIncreaseNumBatches (or perhaps
> ExecHashJoinSaveTuple for symmetry with the above)?  Otherwise you
> might have to wait for a few hundred MB of tuples to be written out
> which could be slow if IO is somehow overloaded.

Mmm, good point.  I think in that case the C.F.I. had better be in
the loop in ExecHashIncreaseNumBatches, because if you were unlucky
the loop might not take the ExecHashJoinSaveTuple path for a long time.

Looking around at other callers of ExecHashJoinSaveTuple, the only one
that seems to be in need of a C.F.I. is the loop in
ExecHashRemoveNextSkewBucket, and there again there's a code path
whereby the loop doesn't call ExecHashJoinSaveTuple.

Will CFI-ify all three places.
        regards, tom lane



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