Re: [REVIEW] Re: Compression of full-page-writes

On 2014-12-12 11:08:52 -0500, Robert Haas wrote:
> Unless I'm missing something, this test is showing that FPW
> compression saves 298MB of WAL for 17.3 seconds of CPU time, as
> against master.  And compressing the whole record saves a further 1MB
> of WAL for a further 13.39 seconds of CPU time.  That makes
> compressing the whole record sound like a pretty terrible idea - even
> if you get more benefit by reducing the lower boundary, you're still
> burning a ton of extra CPU time for almost no gain on the larger
> records.  Ouch!

Well, that test pretty much doesn't have any large records besides FPWs
afaics. So it's unsurprising that it's not beneficial.

Greetings,

Andres Freund