On Thu, Dec 1, 2016 at 6:17 PM, Michael Paquier <michael.paqu...@gmail.com> wrote:
> On Thu, Dec 01, 2016 at 05:48:51PM +0200, Achilleas Mantzios wrote: > > > > Performance is the reason. You would benefit from moving pg_xlog to a > > different controller with its own write cache or to a different SSD with > a > > write cache which is capacitor-backed. So in enterprise/server-class > setups > > the above would boost the performance. Using the same SSD with a > different > > partition won't give you much. > > For performance, on-disk write pattern of data in pg_xlog is sequential > writes, while there will be likely random writes on the main data folder. > This is only the case if you have a write cache, or are doing bulk loads. With small transactions and without a write cache, the need for constant syncs totally destroys the benefits of sequential writes. Cheers, Jeff
