Re: Heavily-loaded MySQL: Resource temporarily unavavailable?

[Chris Boot]

Jay Pipes wrote:
>>> Other variables you may want to look at is ensuring that your 
>>> table_cache (or table_open_cache if 5.1+) has enough room to deal 
>>> with 600 connections * the number of average tables in a typical SQL 
>>> expression executed against the server.  If this variable value is 
>>> really low, you could be experiencing file descriptor swap/thrashing 
>>> as so many threads are opening and then closing file descriptors 
>>> rapidly.
>>
>> table_cache is set to 512, which is probably a little low for my 
>> environment but it seems ok for now (opened_tables is about 3K after 
>> 4 hours MySQL uptime).
>
> If you've adjusted your ulimit for file descriptors, then, sure, put 
> this up soe that not as much thrashing occurs.

Let me just check before I start doing this that the rlimit is adjusted 
using open_files_limit? It's currently set to 4000 and I don't think 
it's ever even got near that number of open files.

I'm still scratching my head about those failed connections. I just 
don't get it.

Thanks,
Chris