Re: Calculating memory allocaiton per process

On Thu, Apr 14, 2011 at 03:00:07PM -0400, Jerry Sievers wrote:
- David Kerr  writes:
- 
- > Howdy, 
- >
- > Is there a doc somewhere that has a formula for how much memory PG
- > backend process will use?
- >
- > I'm looking to get something like total_mem = max_connections * (
- > work_mem + temp_buffers ) // I know it's more complicated than that,
- > which is why I'm asking =)
- 
- Depends on your query complexity, load distribution across concurrent
- sessions and session lifetime.
- 
- work_mem will, in cases of queries having multiple sort nodes, have to
- be counted multiple times on behalf of a single backend.
- 
- Some observation of the running system can be your best bet.
- 
- HTH

Yeah, that's the complication that I knew about (but am still not able to
fully 'get', let along vocalize). 

Are there no rules of thumb or upper bounds to help estimate total memory usage?

Thanks

Dave