Skip site navigation (1) Skip section navigation (2)

Re: Performance issue with Insert

From: Jenish <jenishvyas(at)gmail(dot)com>
To: tv(at)fuzzy(dot)cz
Cc: Kevin Grittner <kevin(dot)grittner(at)wicourts(dot)gov>, pgsql-performance(at)postgresql(dot)org
Subject: Re: Performance issue with Insert
Date: 2011-06-27 15:58:26
Message-ID: BANLkTim-QmRMR4husxhEJmUfihPv6mUp4Q@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
Hi,

I have already checked all the statements present in the trigger, no one is
taking more then 20 ms.

I am using 8-Processor, Quad-Core Server ,CPU utilization is more then 90-95
% for all. (htop result)

DB has 960 concurrent users.

io : writing 3-4 MB per second or less (iotop result).

Scenario :  All insert are waiting for previous insert to complete. Cant
we avoid this situation ?
What is the "max_connections" postgresql support?

Plz help....


-- 
Thanks & regards,
JENISH VYAS






On Mon, Jun 27, 2011 at 6:32 PM, <tv(at)fuzzy(dot)cz> wrote:

> > Hi,
> >
> > DB : POSTGRES 8.4.8
> > OS  : Debian
> > HD : SAS 10k rpm
> >
> > Shared_buffer is 4096 25 % of RAM , effective_cache is 8GB 75% of RAM
> >
> > After insert trigger is again calling 2 more trigger and insert record in
> > another table depends on condition.
> >
> > with all trigger enable there are 8 insert and 32 updates(approx. update
> > is
> > depends on hierarchy)
>
> Hi,
>
> it's very difficult to give you reliable recommendations with this little
> info, but the triggers are obviously the bottleneck. We have no idea what
> queries are executed in them, but I guess there are some slow queries.
>
> Find out what queries are executed in the triggers, benchmark each of them
> and make them faster. Just don't forget that those SQL queries are
> executed as prepared statements, so they may behave a bit differently than
> plain queries. So use 'PREPARE' and 'EXPLAIN EXECUTE' to tune them.
>
> > Plz explain multiple connections. Current scenario application server is
> > sending all requests.
>
> PostgreSQL does not support parallel queries (i.e. a query distributed on
> multiple CPUs) so each query may use just a single CPU. If you're CPU
> bound (one CPU is 100% utilized but the other CPUs are idle), you can
> usually parallelize the workload on your own - just use multiple
> connections.
>
> But if you're using an application server and there are multiple
> connections used, this is not going to help you. How many connections are
> active at the same time? Are the CPUs idle or utilized?
>
> Tomas
>
>

In response to

Responses

pgsql-performance by date

Next:From: Merlin MoncureDate: 2011-06-27 16:12:02
Subject: Re: Performance issue with Insert
Previous:From: tvDate: 2011-06-27 15:37:43
Subject: Re: Long Running Update - My Solution

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group