Re: When should I start and setup a slave replication? - Mailing list pgsql-novice

From Tomer Praizler
Subject Re: When should I start and setup a slave replication?
Date
Msg-id CAD=kdR_Nx0aHJr0ps9=-+qWWRVG8OkvJ2gUw-EX2M-QBa6WNwQ@mail.gmail.com
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In response to Re: When should I start and setup a slave replication?  (Laurenz Albe <laurenz.albe@cybertec.at>)
List pgsql-novice
Thanks!
 - So I see both CPU and I/O load.
 - I have found many problematic queries and optimized them, but there are some which cannot be optimized anymore. 
 - I have added all indexes needed to make my queries faster. 
 - I am trying to "squeeze the lemon" more before I use the help of an advisor, this is why I asked about those interesting metrics. 

I use postgres 10.1. Should I try and play with the workers configuration to optimize for example aggregations queries? 

I am trying to understand when should I use a hot standby configuration assuming all (most) of my queries are optimized.

Any other ideas?

On Sun, 4 Feb 2018 at 23:57 Laurenz Albe <laurenz.albe@cybertec.at> wrote:
Tomer Praizler wrote:
> I currently have one Postgres server running on an ec2 instance 32GB, and 8 cores.
> My DB is under a heavy load and sometimes queries might get super slow.
> I guess it is doing too much and has many access patterns which don't let it optimize correctly.
>
> I wonder if introducing a slave replication (making all reads going to the slave,
> and writes to the master) will make my setup more performant.
> Are there any good metrics to measure before making such decision?
> I really want to be able to see the improvement in case I decide to go with setting a replication.

Before you decide on measures, you have to determine the cause of the problem.

- Is it I/O or CPU load?
- What queries are causing the biggest load?

Very often, a few CREATE INDEX can take care of the problem quite nicely.
Perhaps hiring a consultant can help.

For many I/O problems, increasing RAM is also a simple way to help.

Yours,
Laurenz Albe

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