Re: Avoid full page images in streaming replication? - Mailing list pgsql-hackers

From Andres Freund
Subject Re: Avoid full page images in streaming replication?
Date
Msg-id 20151022220330.GH14196@alap3.anarazel.de
Whole thread Raw
In response to Avoid full page images in streaming replication?  (Jim Nasby <Jim.Nasby@BlueTreble.com>)
Responses Re: Avoid full page images in streaming replication?  (Jim Nasby <Jim.Nasby@BlueTreble.com>)
Re: Avoid full page images in streaming replication?  (Bernd Helmle <mailings@oopsware.de>)
List pgsql-hackers
On 2015-10-22 16:34:38 -0500, Jim Nasby wrote:
> ISTM it should be possible to avoid sending full page writes to a streaming
> replica once the replica has reached a consistent state. I assume that the
> replica would still need to write full pages to it's disk in case of a
> crash, but the sender could insert special WAL records to tell it when to do
> so, instead of sending the full page image. Presumably this would be a big
> win for replication over a WAN.

Note that FPIs are often pretty good for replay performance, avoiding
lots of synchronous random reads.

I think FPI compression is a better solution for now. I found it to be
extremely effective in some benchmarks I recently ran.

Andres



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