Performance problems after upgrading MySql from 4.1.20 to 5.0.22

[Diegorg]

Hi all !

I was using zabbix 1.4.2, mysql 4.1.20 , Red Hat 4 and PHP 4.
Now I'm using zabbix 1.4.4, Red Hat 5, PHP 5 and mysql 5.0.22.

The problem is that when I was using version 4.1.20, mysqld process was using around 18% of the total server memory, which is 2 GB.

Now that I upgraded to mysql version 5.0.22 mysqld process is using 65% of the total server memory and the server is very slow... I don't know what happened...

Mysql is using Innodb engine...

Here is the principal part of my file /etc/my.cnf:

query_cache_type=0
query_cache_size = 512k
key_buffer_size = 512k
join_buffer_size = 4M
long_query_time = 5
table_cache = 64M
sort_buffer = 8M
read_buffer_size = 8M
max_connection = 200
thread_cache = 40
max_heap_table_size = 128M
tmp_table_size = 64M
innodb_buffer_pool_size = 900M
innodb_additional_mem_pool_size = 20M

I appreciate any kind of help...

Thanks, Diego.