single UPDATE query takes 1.5 seconds!!!

[Andrej Pirman]

Hello!

I was dealing with slow PHP 5.1 / MySQL 4.1.12a combination on Windows 2003 server with IIS 6.0. And I found interesting detail:
this UPDATE query took 1.3 - 1.8 seconds to execute on Dual Xeon 3.06 GHz machine with >1GB free RAM!!!

--- query ---
UPDATE sms_log SET delivered_date="2005-07-15 12:38:53", send_date="", delivered_status="done" WHERE msg_id="624j81hmce14a712ptih8l9y" AND to_user RLIKE 41568147;
---/query ---

I was executing query from phpMyAdmin tool, and also directly from Command Prompt console using .sql script. In both cases execution times were similar:

--- console ---
mysql> USE sms_database
Database changed
mysql> SOURCE update_test.sql

Query OK, 0 rows affected, 1 warning (1.52 sec)
Rows matched: 1 Changed: 0 Warnings: 1
---/console ---

Any idea why such simple query would take so much time?