Re: recovery testing for beta

On Sat, May 31, 2014 at 3:51 AM, Jeff Janes <jeff.janes@gmail.com> wrote:
> On Thu, May 29, 2014 at 8:15 PM, Amit Kapila <amit.kapila16@gmail.com> wrote:
>> On Thu, May 29, 2014 at 10:09 PM, Jeff Janes <jeff.janes@gmail.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.