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Multiple database connections

Is there a disadvantage using multiple database connections?

10:58 pm on Oct 21, 2010 (gmt 0)

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joined:May 2, 2004
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MySQL 4.1.25
PHP 5.2.13

I have a site that is geting quite large and needs reorganising.

Instead of using one database with multiple tables with prefixes such as user_, directory_, events_, tracking_ etc. I was thinking of using multiple databases and place all the tables required for that function into that database.

This would mean multiple connections:

$conn_users = mysql_connect('localhost',$user_users,$pass_users);
$conn_track = mysql_connect('localhost',$user_tracker,$pass_tracker,TRUE);
$conn_dir = mysql_connect('localhost',$user_directory,$pass_directory,TRUE);
$conn_events = mysql_connect('localhost',$user_events,$pass_events,TRUE);


I was just wondering if using multiple databases and connections this way will create performance or memory issues.

Comments/advice please.
10:40 am on Oct 22, 2010 (gmt 0)

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I would expect a performance hit with multiple databases. So right now with each page request, your server performs a single db connection. With multiple dbs each request will cause 4 connections based on what you said. That may cause greater latencies than what queries cause.

If you can simplify the db structure and optimize the queries its possible to avoid it.