Re: Regression test coverage of GiST index build is awful - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Regression test coverage of GiST index build is awful
Date
Msg-id 12006.1556133795@sss.pgh.pa.us
Whole thread Raw
In response to Re: Regression test coverage of GiST index build is awful  (Alexander Korotkov <a.korotkov@postgrespro.ru>)
List pgsql-hackers
Alexander Korotkov <a.korotkov@postgrespro.ru> writes:
> On Wed, Apr 24, 2019 at 9:31 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Why is this so bad?  It's not like the gist regression test isn't
>> ridiculously expensive already; I'd have expected it to provide
>> darn near 100% coverage for what it's costing in runtime.

> I don't think there is any idea behind this.  Seems to be just oversight.

After poking at it a bit, the answer seems to be that the gist buffering
code isn't invoked till we get to an index size of effective_cache_size/4,
which by default would be way too much for any regression test index.

> Do you like me to write a patch improving coverage here?

Somebody needs to... that's an awful lot of code to not be testing.

            regards, tom lane



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