How many memory a backend process use ?

Hi,

We are testing the postgreSQL in SUN sparc solaris 7 with 2 CPU of
400Mhz and 512M memory.

I started the postmaster with 'postmaster -i -N 1024 -B 4000'. In the
future my web application can have the max connection supported.

I tested this server with a VB program with ODBC connection.
I noticed that the insertion is too slow :
the time of (onnection+insertion of 100 rows + disconnet)  is 10
seconds.

Could you please  help-me in this two questions ?

1. If I started the postmaster with <-o F > option I will inprove the
performance but I will loose the latest data if have crash.
    Could you tell me how many minutes postgres will spend to put the
transactions in disk?
    Is this time dependent or transactions log depent ? Or neither of
them?

2. I can see by command < ipcs -am > that postgres alloc 46M of shared
memory.
   And I can see by command < top > that the size of postgres servers
for each client is 50M.
   So each postgres client spend 4M of memory. If I have 1024 clients I
will spend 4M* 1024 (max connection) = 4192M.
   Is my conclusion correct? I only made 50M-46M(shared memory).

   Do you think 1G of RAM and 4G swap is enough for may application?
   (my application is not heavy. It has a lot of select by userid and
some atualization in batch or by web)

Thanks in advance. I would apreciate any help. And sorry for my English.

Geny

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Geny Matsui
Promon*IP
Fone 11-3847-4724
Email: geny.matsui@promon.com.br
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