Re: [HACKERS] Will switchover still need a checkpoint in 9.1 SR Hot Standby

2011-08-07 Thread Simon Riggs
On Sun, Aug 7, 2011 at 8:57 AM, Hannu Krosing ha...@2ndquadrant.com wrote:
 In 9.0 (as in earlier versions) a former standby host has to do a full
 checkpoint before becoming available as an independent database instance
 in either switchover or failover scenarios.

 For most combinations of of bigger than minimal shared buffers and
 non-memory-speed disks this can take from several seconds to tens of
 minutes on busy systems.

For switchover, you issue a checkpoint first, to reduce this time as
much as possible.

 Is the pre-activation checkpoint still required in 9.1 ?

Yes, but I've found a way to remove them in 9.2 and will be patching that soon.

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Re: [HACKERS] Will switchover still need a checkpoint in 9.1 SR Hot Standby

2011-08-07 Thread PostgreSQL - Hans-Jürgen Schönig

On Aug 7, 2011, at 11:01 AM, Simon Riggs wrote:

 On Sun, Aug 7, 2011 at 8:57 AM, Hannu Krosing ha...@2ndquadrant.com wrote:
 In 9.0 (as in earlier versions) a former standby host has to do a full
 checkpoint before becoming available as an independent database instance
 in either switchover or failover scenarios.
 
 For most combinations of of bigger than minimal shared buffers and
 non-memory-speed disks this can take from several seconds to tens of
 minutes on busy systems.
 
 For switchover, you issue a checkpoint first, to reduce this time as
 much as possible.
 
 Is the pre-activation checkpoint still required in 9.1 ?
 
 Yes, but I've found a way to remove them in 9.2 and will be patching that 
 soon.



hi simon,

this is highly interesting. this is am important issue for big iron.
can you share the idea you have in mind?

many thanks,

hans


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