> I don't feel that another source of the performance dip has been heartily
> addressed; full-page-write rush, which I call here, would be a major issue.
> That is, the average size of transaction log (XLOG) records jumps up sharply
> immediately after the beginning of each checkpoint, resulting in the
> saturation of WAL write path including disk(s) for $PGDATA/pg_xlog and WAL
> buffers.
On this point, you may have a look at this item:
https://commitfest.postgresql.org/5/283/
--
Fabien.