Windows 2000 Advance Server (latest service pack)
Physical Address Extension enabled
Dual 2.4Ghz Intel Pentium 4 Xeon
6gb of memory
This system is running as a dedicated MySQL 4.0.12-max-nt server.
Issue: The problem first exhibited itself as a connection issue. We
weren't able to obtain more than 250 active connections. After
troubleshooting we found that lowering the innodb_buffer_pool_size variable
increased the number of available active connections. The
innodb_buffer_pool_size was originally set at 1500M. Further investigation
has determined that MySQL isn't able to use more than 2gb of memory on this
system. It is our understanding that with PAE(Physical Address Extension)
enables on the system that MySQL should be able utilize more than 2gb of
memory. To prove that we were having problems with the 2gb memory limit we
increased the innodb_buffer_pool_size to 2500M. At that time the MySQL
service wouldn't start.
We currently have the innodb_buffer_pool_size set to 1000M which is giving
us the possibility of having about 650 active connections in MySQL.
Does anyone have any suggestions as to what would be causing the memory
limitation in MySQL?