amolarakh at yahoo
Mar 29, 2011, 11:32 PM
Post #2 of 2
Re: High latency when port-forwarding postgresql (for statements which don't return data)
[In reply to]
There are various scenarios for decreased latency.
1. Kindly check the host entry if dbserver is internal and not
communicating to Internet
2. Please traceroute/ use sniffer on forwarded port will give you exact
On Tuesday 22 March 2011 07:05 PM, Clemens Eisserer wrote:
> I experience a very strange problem, when using the jdbc driver with
> ssh's local port forwarding:
> ssh -v -L 4321:dbserver:5432 user [at] dbserve
> SELECT statements show about the same latency as without
> port-forwarding (and even decreased latency when compression is
> enabled), but sometimes UPDATE/DELETE statements take seconds to
> The other time they are as fast as they should be. When I connect to
> postgres without port-forwarding the update statements consistently
> take only a few milliseconds.
> Any idea what the reason could be, I've tested it with two different
> ssh clients (one java, and openssh) both show the same behaviour.
> Could it be some buffering on the server side, to make data transfer
> more efficient?
> Could it be because selects usually send a lot of data back to the
> client, buffering doesn't hurt - but for update/delete usually only a
> acknoledgement is sent back and buffering starts to be an issue?
> Thank you in advance, Clemens
> Btw the java-based client seems to be waiting for data while it
> executes the statements:
> java.net.SocketInputStream.socketRead0(Native Method)
> - locked org.postgresql.core.v3.QueryExecutorImpl [at] 17b168