Re: Speed up Clog Access by increasing CLOG buffers

On Fri, Mar 10, 2017 at 11:51 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> writes:
>> Just to let you know that I think I have figured out the reason of
>> failure. If we run the regressions with attached patch, it will make
>> the regression tests fail consistently in same way. The patch just
>> makes all transaction status updates to go via group clog update
>> mechanism.
>
> This does *not* give me a warm fuzzy feeling that this patch was
> ready to commit. Or even that it was tested to the claimed degree.
>

I think this is more of an implementation detail missed by me. We
have done quite some performance/stress testing with a different
number of savepoints, but this could have been caught only by having
Rollback to Savepoint followed by a commit. I agree that we could
have devised some simple way (like the one I shared above) to test the
wide range of tests with this new mechanism earlier. This is a
learning from here and I will try to be more cautious about such
things in future.

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com