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Hi Chris,<br>
<br>
Thank you for the out-of-the-box idea. If MySQL was trying to do
inverse DNS it would certainly fail the way you describe because we
have not set it up. However I am not sure about that because when the
link is not saturated, MySQL responds right away to the same requests
or queries. I will try adding a /etc/hosts entry on the linux server
end for the client IP address and see if it is any better.<br>
<br>
Thanks,<br>
Jim<br>
<br>
chris fedde wrote:
<blockquote
cite="mid:7de3d64f0911090636t5cf25c0ub6ceefc1f4ca433c@mail.gmail.com"
type="cite">
<pre wrap="">Having read through this thread I begin to wonder if it is a DNS
issue. mysql may be looking for and failing to find reverse dns
entries. The characteristic for this particular problem is a 90
second delay from the tcp connection till the response banner.
You can check to see if this is the issue using tcpdump.
On Sun, Nov 8, 2009 at 9:17 PM, Jim Ockers <a class="moz-txt-link-rfc2396E" href="mailto:ockers@ockers.net"><ockers@ockers.net></a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi Dave,
David L. Anselmi wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Jim Ockers wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Whenever there is sustained high bandwidth network traffic over the PPP
link (such as downloading a large e-mail attachment, or streaming video) the
mysql connections all start to time out because response packets from the
server are not received at the client. I observed this by doing a simple
"telnet server 3306" and observed that the MySQL banner response with
version number was delayed by several seconds or until the bandwidth-hogging
stopped.
What I don't understand is why I can still transfer data from other
servers on the Linux system, such as "net view \\server" and "dir
\\server\sharename" (using the Windows redirector to talk to Samba on the
Linux system). Also the apache web server on the Linux system responds
normally, both from a web browser and also in response to "telnet server 80"
and then "GET / HTTP/1.0".
</pre>
</blockquote>
<pre wrap="">I assume that other services are delayed like the MySQL banner. Most of
what you tried though would use fairly small responses (one packet, even?)
so maybe the MySQL protocol is more verbose.
</pre>
</blockquote>
<pre wrap="">No, actually the only service that is delayed is MySQL response packets
including the banner. Apache responds right away to a GET / HTTP/1.0
request, samba responds right away to a Windows redirector request, FTP
responds right away, and so forth. MySQL is the only one that seems to take
an unreasonably long time to respond when there is something hogging the
bandwidth.
</pre>
<blockquote type="cite">
<pre wrap="">It seems that clients have several timeouts available:
<a class="moz-txt-link-freetext" href="http://dev.mysql.com/doc/refman/5.1/en/mysql-options.html">http://dev.mysql.com/doc/refman/5.1/en/mysql-options.html</a>
Maybe the protocol takes too long in some cases.
</pre>
</blockquote>
<pre wrap="">I'm not too sure about that, but since the banner is delayed I wonder if
MySQL has some sort of built-in congestion management or something.
Thanks though,
Jim
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</blockquote>
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