Re: recovery testing for beta

On Sat, May 31, 2014 at 3:51 AM, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:
> On Thu, May 29, 2014 at 8:15 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
wrote:
>> On Thu, May 29, 2014 at 10:09 PM, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
wrote:
>> >
>> > What features in 9.4 need more beta testing for recovery?
>>
>> Another feature which have interaction with recovery is reduced WAL
>> for Update operation:
>>
http://www.postgresql.org/message-id/E1WNqjM-0003cz-EL@gemulon.postgresql.org
>>
>> Commit: a3115f
>
>
> It looks like this is something which is "always on", so it should be
getting a good test without me taking any special steps. But is there some
way, for example something in xlogdump, to assess how often this is getting
activated?

Currently there is no simple way to get this information, but with
attached simple patch you can get this information by pg_xlogdump.

It will give you information in below way:

rmgr: Heap len (rec/tot): 47/ 79, tx: 690, lsn:
0/0375B4A0,
prev 0/0375B470, bkp: 0000, desc: hot_update: rel 1663/12125/24580; tid
0/1 xma
x 690 ; new tid 0/2 xmax 0; *compressed tuple:* *suffix encoded*

rmgr: Heap len (rec/tot): 53/ 85, tx: 691, lsn:
0/0375B520,
prev 0/0375B4F0, bkp: 0000, desc: hot_update: rel 1663/12125/24580; tid
0/2 xma
x 691 ; new tid 0/3 xmax 0; *compressed tuple: prefix encoded*

rmgr: Heap len (rec/tot): 56/ 88, tx: 692, lsn:
0/0375B5A8,
prev 0/0375B578, bkp: 0000, desc: hot_update: rel 1663/12125/24580; tid
0/3 xma
x 692 ; new tid 0/4 xmax 0; *uncompressed tuple*

I think this is useful information and can be even included in core
code.

With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com