Em ter., 13 de jul. de 2021 às 01:14, r.takahash...@fujitsu.com <
r.takahash...@fujitsu.com> escreveu:
> Hi Sawada-san,
>
>
> Thank you for your reply.
>
> > Not sure but it might be possible to keep holding an xlogreader for
> > reading PREPARE WAL records even after the transaction commit. But I
> > wonder how much open() for wal segment file accounts for the total
> > execution time of 2PC. 2PC requires 2 network round trips for each
> > participant. For example, if it took 500ms in total, we would not get
> > benefits much from the point of view of 2PC performance even if we
> > improved it from 14ms to 1ms.
>
> I made the patch based on your advice and re-run the test on the new
> machine.
> (The attached patch is just for test purpose.)
>
Wouldn't it be better to explicitly initialize the pointer with NULL?
I think it's common in Postgres.
static XLogReaderState *xlogreader = NULL;
>
> * foreign_twophase_commit = disabled
> 2686tps
>
> * foreign_twophase_commit = required (It is necessary to set -R ${RATE} as
> Ikeda-san said)
> 311tps
>
> * foreign_twophase_commit = required with attached patch (It is not
> necessary to set -R ${RATE})
> 2057tps
>
Nice results.
regards,
Ranier Vilela
