On 6/9/21 8:28 AM, Tom Lane wrote:
I wrote:
Bharath Rupireddy <bharath.rupireddyforpostg...@gmail.com> writes:
I've added a simple regression test to postgres_fdw, testing that batch
sizes > 65535 work fine, and pushed the fix.
I was earlier thinking of adding one, but stopped because it might
increase the regression test execution time. It looks like that's true
- with and without the test case it takes 17 sec and 4 sec
respectively on my dev system which is 4X slower. I'm not sure if this
is okay.
The cost, versus the odds of ever detecting a problem, doesn't
seem like a good tradeoff.
I took a quick look and noted that on buildfarm member longfin
(to take a random example that's sitting a few feet from me),
the time for contrib-install-check went from 34 seconds before
this patch to 40 seconds after. I find that completely
unacceptable compared to the likely value of this test case.
Note that the problem here is [1] - we're creating a lot of slots
referencing the same tuple descriptor, which inflates the duration.
There's a fix in the other thread, which eliminates ~99% of the
overhead. I plan to push that fix soon (a day or two).
regards
--
Tomas Vondra
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
