Re: [HACKERS] Use sync commit for logical replication apply in TAPtests

On 4/20/17 09:46, Petr Jelinek wrote:
> On 20/04/17 14:57, Peter Eisentraut wrote:
>> On 4/18/17 22:25, Petr Jelinek wrote:
>>> The commit 887227a1c changed the defaults for subscriptions to do async
>>> commit. But since the tests often wait for disk flush and there is no
>>> concurrent activity this has increased the amount of time needed for
>>> each test. So the attached patch changes the subscriptions create in tab
>>> tests to use sync commit which improves performance there (because we
>>> also replicate only very few transactions in the tests).
>>
>> I see only a 1.5% (1s/70s) improvement in the run time of the whole test
>> suite from this.  Is that what you were expecting?
> 
> Hmm, on my machine the difference is around 50% (~1m vs ~2m).

Double hmm, I ran a few more tests and different machines and get
consistent but underwhelming improvements.

I don't mind applying the patch nonetheless, but maybe we can get a few
more test results from others.

(Instructions: apply the patch and time make -C src/test/subscription check)

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services