Forum OpenACS Development: Re: maxidle and maxopen
Btw, reducing connections from 5 to 1 might reduce memory, but the same time your are reducing greatly the ability to run db-queries in parallel. If you have multiple http requests running, and all of these require handles from the pools, and you have ony 1 connection configured, the queries are sequentialized, since each query has to wait until a db connection is available. This means that he waiting time for handles will go up. If most of your http requests use the database the value for maxthreads must be aligned with connections. On our main site, we have 90 connections configured.
I do agree that the change in the "connection" value reduces the ability to run db-quesires in parallel.
Cheers and thanks,
there are no significant changes on my sites. I altered the configuration between Sat. and Sun. On Sat we had 421370 hits, on Sun 488751. The chart shows that the growth of the virtual size is happening with and without the MaxIdle/MaxOpen = 0 settings: http://media.wu-wien.ac.at/download/nsdsize-week-2007-03-26.png
Btw, the M should be a G in the chart. Also my other installation did not show improvements.
How did you measure savings? Is this maybe Windows specific?
ns_section ns/db/pool/pool1 ns_param maxidle 60 instead of 1000000000 ns_param maxopen 360 instead of 1000000000 ns_param connections 1 instead of 5 PID MINFLT MAJFLT VSTEXT VSIZE RSIZE VGROW RGROW MEM CMD 1/11 4143 17341 0 1K 51036K 33860K 51036K 33860K 3% nsd 4146 10226 0 2140K 135.0M 27376K 135.0M 27376K 2% postmaster 4147 1204 0 2140K 132.8M 4964K 132.8M 4964K 0% postmaster 3874 58 0 2140K 131.8M 3084K 0K 4K 0% postmaster 4148 638 0 2140K 132.3M 2716K 132.3M 2716K 0% postmaster ATOP - icaro 2007/03/22 17:44:27 600 seconds elapsed PID MINFLT MAJFLT VSTEXT VSIZE RSIZE VGROW RGROW MEM CMD 1/7 4143 10433 0 1K 66576K 47568K 15540K 13708K 4% nsd 4192 69619 0 2140K 134.9M 110.0M 134.9M 110.0M 9% postmaster 4203 998 0 2140K 132.6M 4144K 132.6M 4144K 0% postmaster 3874 59 0 2140K 131.8M 3084K 0K 0K 0% postmaster 3878 7 0 2140K 6472K 892K 0K 0K 0% postmaster ATOP - icaro 2007/03/22 17:54:27 4143 2374 0 1K 66576K 47560K 0K -8K 4% nsd 4239 1039 0 2140K 132.6M 4312K 132.6M 4312K 0% postmaster 3874 47 0 2140K 131.8M 3084K 0K 0K 0% postmaster 3878 5 0 2140K 6472K 892K 0K 0K 0% postmaster 3877 0 0 2140K 7304K 712K 0K 0K 0% postmasterAfter the first set of data I stayed put (i.e. I did not touch/used the system) and as you can see in the following sets of data that PostgreSQL released some memory (have a look at the VSIZE value). When I was using timeouts with values of 1000000000 or of 0 the memory did not get released by PostgreSQL.
Yes it is true, I put some very short timeouts. But I did that to observe some changes in the allocated memory as soon as possible.
Hope it helps,