Re: Summary and Plan for Hot Standby

Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>

From: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
To: Simon Riggs <simon@2ndQuadrant.com>
Cc: pgsql-hackers@postgresql.org
Date: 2009-11-15T14:50:03Z
Lists: pgsql-hackers
Simon Riggs wrote:
> On Sun, 2009-11-15 at 16:07 +0200, Heikki Linnakangas wrote:
>> - If WAL recovery runs out of lock space while acquiring an
>> AccessExclusiveLock on behalf of a transaction that ran in the master,
>> it will FATAL and abort recovery, bringing down the standby. Seems like
>> it should wait/cancel queries instead.
> 
> Hard resources will always be an issue. If the standby has less than it
> needs, then there will be problems. All of those can be corrected by
> increasing the resources on the standby and restarting. This effects
> max_connections, max_prepared_transactions, max_locks_per_transaction,
> as documented.

There's no safe setting for those that would let you avoid the issue. No
matter how high you set them, it will be possible for read-only backends
to consume all the lock space, causing recovery to abort and bring down
the standby.

-- 
  Heikki Linnakangas
  EnterpriseDB   http://www.enterprisedb.com