Re: Should we cacheline align PGXACT?

Hi, Ashutosh!

On Mon, Feb 20, 2017 at 1:20 PM, Ashutosh Sharma <ashu(dot)coek88(at)gmail(dot)com>
wrote:

> Following are the pgbench results for read-write workload, I got with
> pgxact-align-3 patch. The results are for 300 scale factor with 8GB of
> shared buffer i.e. when data fits into the shared buffer. For 1000 scale
> factor with 8GB shared buffer the test is still running, once it is
> completed I will share the results for that as well.
>
> *pgbench settings:*
> pgbench -i -s 300 postgres
> pgbench -M prepared -c $thread -j $thread -T $time_for_reading postgres
>
> where, time_for_reading = 30mins
>
> *non default GUC param:*
> shared_buffers=8GB
> max_connections=300
>
> pg_xlog is located in SSD.
>

Thank you for testing.
It seems that there is still regression. While padding was reduced from
116 bytes to 4 bytes, it makes me think that probably there is something
wrong in testing methodology.
Are you doing re-initdb and pgbench -i before each run? I would ask you to
do the both.
Also, if regression would still exist, let's change the order of versions.
Thus, if you run master before patched version, I would ask you to run
patched version before master.

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company