Thanks Shawn. Do you know why anyone would ever need the reconnect flag
then? The MySQL developers must think that it has a purpose since they
opened up the API to allow access to it from the client. What would be its
purpose otherwise?
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: "Betty Trakimas" <[EMAIL PROTECTED]>
Cc: <mysql@lists.mysql.com>
Sent: Tuesday, November 22, 2005 12:06 PM
Subject: Re: Setting the reconnect flag in MySQL 4.0.24
"Betty Trakimas" <[EMAIL PROTECTED]> wrote on 11/22/2005 11:08:51 AM:
Hello,
We just upgraded from 3.23.58 to 4.0.24. Our database connection, which
can
remain open for a very long time, is timing out after being idle
overnight,
where it never had in 3.23.58. I learned from the manual that there is
a
global variable WAIT_TIMEOUT, which appears to be set at 28800 seconds
(8
hrs) by default. I can set this value to some larger amount, say 7
days,
but that may not be long enough depending on how our customers use our
product. In version 5.0.13 I can call mysql_options() with
MYSQL_OPT_RECONNECT set to true to enable automatic reconnection to the
server if the connection has been lost. I think this is really what I
want
to do instead of setting the WAIT_TIMEOUT variable to a large value. Is
there any way to set this reconnect flag in the 4.0.24 version
programatically? How?
Betty
Any application that depends on a connection to another application in
order to function correctly should be robust enough to deal with the
temporary or permanent loss of that connection without causing too much of
a problem. It doesn't matter what kind of other application your
application needs to connect with, if it cannot handle a loss of
communications without breaking it is poorly designed.
The reconnect flag is part of the client (your application) and how it
makes its connection to the MySQL server. RTFM for the specific library
your application is using for it's MySQL connectivity. It will have
details on how to manage that flag.
Most server-friendly applications only make connections when they need
something. Tying up a network socket overnight for little or no traffic
just wastes server-side resources. I am not recommending a new connection
for EVERY query, once per process is generally enough. I am recommending
that you look at your original application's design and fix it so that
your users won't complain every time it loses connectivity with the
database on the back end. There are more causes of LOC (loss of
communication) other than the server reaching it's timeout value so fixing
that will improve the overall reliability of your application.
Shawn Green
Database Administrator
Unimin Corporation - Spruce Pine
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