Re: [HACKERS] Checkpoints vs restartpoints

2015-06-10 Thread Andres Freund
On 2015-06-10 11:20:19 +1200, Thomas Munro wrote: > I was wondering about this in the context of the recent multixact > work, since such configurations could leave you with different SLRU > files on disk which in some versions might change the behaviour in > interesting ways. Note that trigger a r

Re: [HACKERS] Checkpoints vs restartpoints

2015-06-09 Thread Michael Paquier
On Wed, Jun 10, 2015 at 9:33 AM, Bruce Momjian wrote: > Ah, so even thought standbys don't have to write WAL, they are fsyncing > shared buffers. Where is the restart point recorded, in pg_controldata? > c Yep. Latest checkpoint's REDO location, or ControlFile->checkPointCopy.redo. During recover

Re: [HACKERS] Checkpoints vs restartpoints

2015-06-09 Thread Bruce Momjian
On Tue, Jun 9, 2015 at 05:20:23PM -0700, Jeff Janes wrote: > On Tue, Jun 9, 2015 at 4:20 PM, Thomas Munro > wrote: > > Hi > > Why do standby servers not simply treat every checkpoint as a > restartpoint?  As I understand it, setting checkpoint_timeout and > checkpoint_segments h

Re: [HACKERS] Checkpoints vs restartpoints

2015-06-09 Thread Jeff Janes
On Tue, Jun 9, 2015 at 4:20 PM, Thomas Munro wrote: > Hi > > Why do standby servers not simply treat every checkpoint as a > restartpoint? As I understand it, setting checkpoint_timeout and > checkpoint_segments higher on a standby server effectively instruct > standby servers to skip some check

[HACKERS] Checkpoints vs restartpoints

2015-06-09 Thread Thomas Munro
Hi Why do standby servers not simply treat every checkpoint as a restartpoint? As I understand it, setting checkpoint_timeout and checkpoint_segments higher on a standby server effectively instruct standby servers to skip some checkpoints. Even with the same settings on both servers, the server