Re: TCP Overhead on Local Loopback

You could try using Unix domain socket and see if the performance improves. A relevant link:

http://stackoverflow.com/questions/257433/postgresql-unix-domain-sockets-vs-tcp-sockets

________________________________
From: Ofer Israeli <oferi(at)checkpoint(dot)com>
To: "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Sent: Sunday, April 1, 2012 4:24 PM
Subject: [PERFORM] TCP Overhead on Local Loopback

Hi
all,
 
We are running
performance tests using PG 8.3 on a Windows 2008 R2 machine connecting locally
over TCP.
In our tests, we
have found that it takes ~3ms to update a table with ~25 columns and 60K
records, with one column indexed.
We have reached this
number after many tweaks of the database configuraiton and one of the changes we
made was to perform the updates in batches of 5K as opposed to the pervious
transaction per event.  Note that our use of batches is to have only one
transaction, but still each of the 5K events is independently SELECTing and
UPDATEing records, i.e. it is not all contained in a stored procedure or
such.
 
Still these times
are too high for us and we are looking to lower them and I am wondering about
the TCP/IP overhead of passing the information back and forth.  Does anyone
have any numbers in what the TCP could cost in the configuration mentioned above
or pointers on how to test it?
 
 
Many
thanks,
Ofer