Brian Dunning wrote:
In one case I do need to jump back and forth between databases that are
on different physical servers. What's the most efficient way to handle
this?
On Aug 2, 2005, at 11:14 AM, Devananda wrote:
Brian Dunning wrote:
My RaQ4 is throwing the "Too many connections" error. Now, it is
getting hit pretty hard by traffic, but I wonder if my coding might
be exacerbating this error.
Due to my relatively lazy structure of includes and functions, my
pages might have half a dozen or so of these (most are to the same
database):
$connection = mysql_connect($db_host, $db_username, $db_password);
mysql_select_db($db_name, $connection);
Is that creating half a dozen connections, even though it's just
one web user?
Yep. Each call to mysql_connect creates a new connection to the
database. If you need to connect to multiple database servers then
you obviously need multiple connections, but if you are only
connecting to one database server, then you should really reuse a
single connection. FYI, the process of creating a new connection
requires substantially more processing time than executing a simple
query (ie, mysql_select_db).
One common practice is to have a single include file which creates
the database connection and instantiates a global variable with the
handle to that connection. Then, all pages which include that file
merely use that handle to communicate with the database.
Regards,
Devananda vdv
Create two connections at the beginning of your script/page, then query
each as you need to. For example,
$connA = mysql_connect("A.server.com",...);
mysql_select_db("$db_name",$connA);
$connB = mysql_connect("B.server.com",...);
mysql_select_db("$another_db_name",$connB);
$hdl_some_query_on_A = mysql_query("SELECT something FROM sometable",
$connA); # this query goes to A.server.com
$hdl_some_query_on_B = mysql_query("SELECT some_other_thing FROM
another_table",$connB); # this one goes to B.server.com
and so on. By storing the resource returned from mysql_connect, you can
tell mysql_query which connection to use, and thus utilize multiple
connections (but only create each connection once).
Regards,
Devananda vdv
--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
