On 11/23/06, Gopal <gopal@xxxxxxxxxxxxxx> wrote:
I have a postgres installation thats running under 70-80% CPU usage while an MSSQL7 installation did 'roughly' the same thing with 1-2% CPU load.
i somehow doubt ms sql server is 35x faster than postgresql in production environments, even on windows.
work_mem = 512 # min 64,
this is probably too low.
SQL server caches all the data in memory which is making it faster(uses about 1.2GB memory- which is fine). But postgres has everything spread across 10-15 processes, with each process using about 10-30MB, not nearly enough to cache all the data and ends up doing a lot of disk reads.
this is a misleading and unfortuante shortcoming of the windows process manager. postgresql uses a lot of shared memory, and if you have shared memory set to 10 mb, each process in the task manager can report up to 10 mb (at the same time) even though only 10mb is really in use.
I've read that postgres depends on OS to cache the files, I wonder if this is not happenning on windows.
Are you suggesting postgresql somehow turned off file caching in windows?
In any case I cannot believe that having 15-20 processes running on windows helps. Why not spwan of threads instead of processes, which might
this was an important arguement in oh, say, 1992 :-). Seriously, even though processes are slower in windows than threads for certain things, it's not as much as you'd expect and certainly not causing any performance issues you are suffering. My question is, should I just accept the performance I am getting as the
limit on windows or should I be looking at some other params that I might have missed?
i'd start by logging queries with execution times and looking for queries that are running the slowest. merlin
