Re: [PERFORM] Performance difference between Slon master and slave

[Mattthew Lunnon]

Hi Jim,
Thanks for your response. Yes the tables have been analysed and I have also 
re-indexed and vacuumed the slave database. 
Regards
Matthew 

Sent from my iPad

> On 14 Dec 2015, at 17:49, Jim Nasby  wrote:
> 
>> On 12/14/15 11:16 AM, Matthew Lunnon wrote:
>> Inspecting the execution plan shows that there are some differences, for
>> example, the slave is using a HashAggregate when the master is simply
>> grouping. There also seems to be a difference with the ordering of the
>> sub plans.
> 
> Have you tried analyzing the tables on the slave?
> 
> Also, keep in mind that the first time you access rows on a Slony slave after 
> they're replicated Postgres will need to write hint bits out, which will take 
> some time. But that's clearly not the issue here.
> -- 
> Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
> Experts in Analytics, Data Architecture and PostgreSQL
> Data in Trouble? Get it in Treble! http://BlueTreble.com


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Re: [PERFORM] Performance difference between Slon master and slave

[Jim Nasby]

On 12/14/15 11:16 AM, Matthew Lunnon wrote:

Inspecting the execution plan shows that there are some differences, for
example, the slave is using a HashAggregate when the master is simply
grouping. There also seems to be a difference with the ordering of the
sub plans.


Have you tried analyzing the tables on the slave?

Also, keep in mind that the first time you access rows on a Slony slave 
after they're replicated Postgres will need to write hint bits out, 
which will take some time. But that's clearly not the issue here.

--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com


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