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

On Tue, Nov 11, 2014 at 5:10 PM, Michael Paquier
<michael(dot)paquier(at)gmail(dot)com> wrote:
> On Mon, Nov 10, 2014 at 5:26 PM, Michael Paquier
> <michael(dot)paquier(at)gmail(dot)com> wrote:
>> I'll go through the patch once again a bit later, but feel free to comment.
> Reading again the patch with a fresher mind, I am not sure if the
> current approach taken is really the best one. What the patch does now
> is looking at the header of the first backup block, and then
> compresses the rest, aka the other blocks, up to 4, and their headers,
> up to 3. I think that we should instead define an extra bool flag in
> XLogRecord to determine if the record is compressed, and then use this
> information. Attaching the compression status to XLogRecord is more
> in-line with the fact that all the blocks are compressed, and not each
> one individually, so we basically now duplicate an identical flag
> value in all the backup block headers, which is a waste IMO.
> Thoughts?

I think this was changed based on following, if I am not wrong.

http://www.postgresql.org/message-id/54297A45.8080904@vmware.com

Regards,
Amit