On Jan 17, 2014, at 5:07 AM, Granthana Biswas <granth...@zedo.com> wrote:

> Yes it's purely for monitoring purpose.
> 


I use the pg_controldata cmd locally and via bash/ssh shared keys and compare 
various values that seem interesting such as "Time of latest checkpoint, Latest 
checkpoint location."  My interest is recoverability and checkpoints seemed 
relevant at the time.  

I found a comment in the docs:

http://www.postgresql.org/docs/9.2/static/functions-admin.html

"pg_xlog_location_diff calculates the difference in bytes between two 
transaction log locations. It can be used with pg_stat_replication or some 
functions shown in Table 9-59 to get the replication lag."

and 
"The functions shown in Table 9-60 provide information about the current status 
of the standby. These functions may be executed both during recovery and in 
normal running."  

These look interesting wrt lag studies and seem to work on the stby:

template1=# select pg_last_xlog_receive_location();
 pg_last_xlog_receive_location 
-------------------------------
 18/9E000000
(1 row)

template1=# select pg_last_xlog_replay_location();
 pg_last_xlog_replay_location 
------------------------------
 18/9E000000
(1 row)



Attachment: signature.asc
Description: Message signed with OpenPGP using GPGMail

Reply via email to