Re: Regression test coverage of GiST index build is awful

Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru> writes:
> On Wed, Apr 24, 2019 at 9:31 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)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