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Thread: Connections "Startup"

Connections "Startup"

From
Artem Tomyuk
Date:
Hi.

I've noticed huge decrease in performance.
During this in htop i see a lot (200 - 300) of connections in state "startup", each of them eats 3-3% of CPU time. This processes are not visible in pg_stat_activity so i cant understand what they are doing, and i cant kill them. I cant see the bottleneck in Disk IO to. The logs of postgres says nothing to. I am confused.....
What can be the cause of  huge amount of "startup" connections.... 
Maybe its better to start use connection pooler such as pgbouncer? 
Thanks a lot.

PS.
Server config is:
2 * Intel Xeon 2660 CPU with 64 gigs of RAM. 
Hardware RAID10.
Centos 6.6, PostgreSQL 9.1.2 



Re: [PERFORM] Connections "Startup"

From
Pavel Stehule
Date:
Hi

2015-12-22 8:59 GMT+01:00 Artem Tomyuk <admin@leboutique.com>:
Hi.

I've noticed huge decrease in performance.
During this in htop i see a lot (200 - 300) of connections in state "startup", each of them eats 3-3% of CPU time. This processes are not visible in pg_stat_activity so i cant understand what they are doing, and i cant kill them. I cant see the bottleneck in Disk IO to. The logs of postgres says nothing to. I am confused.....
What can be the cause of  huge amount of "startup" connections.... 
Maybe its better to start use connection pooler such as pgbouncer? 
Thanks a lot.

What is your max_connections? Can you ran "perf top" ? What is there.

Too high number can enforce system overloading. You cannot to see these connections in pg_stat_activity because the process in this state isn't fully initialized.

There was lot of bugfix releases after 9.1.2 - currently there is PostgreSQL 9.2.19. Try to upgrade first.

Regards

Pavel
 

PS.
Server config is:
2 * Intel Xeon 2660 CPU with 64 gigs of RAM. 
Hardware RAID10.
Centos 6.6, PostgreSQL 9.1.2 




Re: [PERFORM] Connections "Startup"

From
Jim Nasby
Date:
On 12/22/15 2:09 AM, Pavel Stehule wrote:
>
> There was lot of bugfix releases after 9.1.2 - currently there is
> PostgreSQL 9.2.19.

I'm sure Pavel meant 9.1.19, not 9.2.19.

In any case, be aware that 9.1 goes end of life next year. You should
start planning on a major version upgrade now if you haven't already.
9.5 should release in January so you might want to wait for that version.
--
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

Re: [PERFORM] Connections "Startup"

From
Om Prakash Jaiswal
Date:
Postgres is designed in this way. It can handle such problem by adopting the following steps:
1.Increase the kernal level parameters:
shmmax and shmall
example for 2GB RAM size for postgres processing is below
vi /etc/sysctl.conf
kernel.shmmax = 2147483648
kernel.shmall = 2883584

similar way you increase the configuration paramater for half of RAM size of your machine.

2. Edit your postgresql.conf file following settings:
a. Increase the number of connection parameter.
 Connection = 500
b.Effective_cache_size = 2GB
c. Shared_memory = 500MB


 



On Wednesday, 23 December 2015 8:04 AM, Jim Nasby <Jim.Nasby@BlueTreble.com> wrote:


On 12/22/15 2:09 AM, Pavel Stehule wrote:

>
> There was lot of bugfix releases after 9.1.2 - currently there is
> PostgreSQL 9.2.19.


I'm sure Pavel meant 9.1.19, not 9.2.19.

In any case, be aware that 9.1 goes end of life next year. You should
start planning on a major version upgrade now if you haven't already.
9.5 should release in January so you might want to wait for that version.
--
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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To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-admin



Re: [PERFORM] Connections "Startup"

From
Pavel Stehule
Date:


2015-12-23 4:52 GMT+01:00 Om Prakash Jaiswal <op12om@yahoo.co.in>:
Postgres is designed in this way. It can handle such problem by adopting the following steps:
1.Increase the kernal level parameters:
shmmax and shmall
example for 2GB RAM size for postgres processing is below
vi /etc/sysctl.conf
kernel.shmmax = 2147483648
kernel.shmall = 2883584

similar way you increase the configuration paramater for half of RAM size of your machine.

2. Edit your postgresql.conf file following settings:
a. Increase the number of connection parameter.
 Connection = 500
b.Effective_cache_size = 2GB
c. Shared_memory = 500MB


increasing max connection when you have these strange issues isn't good advice. Running 500 connections on 2GB server is highly risky.

Pavel
 

 



On Wednesday, 23 December 2015 8:04 AM, Jim Nasby <Jim.Nasby@BlueTreble.com> wrote:


On 12/22/15 2:09 AM, Pavel Stehule wrote:

>
> There was lot of bugfix releases after 9.1.2 - currently there is
> PostgreSQL 9.2.19.


I'm sure Pavel meant 9.1.19, not 9.2.19.

In any case, be aware that 9.1 goes end of life next year. You should
start planning on a major version upgrade now if you haven't already.
9.5 should release in January so you might want to wait for that version.
--
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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To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-admin