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My application is running out of processes. It seems like it will need about 200. Is that a lot? Whats the max number Oracle can handle and how much memory does oracle need per connection. Whats a good rule of thumb for calculation of connections...

I can find any good information on this issue, so any help greatly appreciated!!


RE: Connections/Processes

Hi Cal,

Memory usage:

I don't have the Oracle documentation to hand so this is from my (probably unreliable) memory.

Allow about 1mb per user (per connection that is.

Add the total size of the SGA (from the init.ora file for that DB)

Add the size of the oracle daemons (use the ps command to find that out)

This is pretty well documented in the "Planning your database" section of the Oracle manuals actually.


This is limited by the operating system rather than Oracle. What operating system are you running the database server under?

Cargill's Corporate Web Site

RE: Connections/Processes

   The max number of processes is set in your init.ora file.  However,
the semaphores parameter in the kernel also needs to be set high
enough to support Oracle and other processes, assuming that you
are on unix.

Jim Carlson

oracle, vb, some javascript

RE: Connections/Processes

Thanks guys.

I'm running the database on HP-UX.

I'm trying to get a handle on this whole connection/process. In SQL Server you open a connection to a database - fair enough, and SS can handle around 65000 of these. With Oracle, as listener22 pointed out, a process can have thousands of threads. So having a hunderd processes can give you hunders of thousands of "pipes" to send  query down (which is a equivalent to a SQL server "connection".

How can I get the kernel parameters - what is the UNIX command?

How come when I connect via JDBC to the database, I'm getting a new Process rather than using an existing process and getting one of its "threads"?

Is this correct, or does it read like the last journal entry from a doomed artic explorer?

Thanks in advance


RE: Connections/Processes

   I'm not sure that I said that a process can have thousands of
threads, but in any case you want to make sure that you have
a backup of your kernel before you make any changes.  If you
have access to meta-link, search on 'semaphores' to get some
idea of the recommended values for kernel parameters.  Or,
see the Oracle installation guide.

Jim Carlson

oracle, vb, some javascript

RE: Connections/Processes


In addition to the init.ora parameter re number of processes (which I didn't know about by the way, thx Jim) there are kernel parameters that limit the number of processes on HPUX. These may need to be modified as well

I'm not an SS guy but it sounds as if SS uses quite different terminology to Oracle. In Oracle you do have the multi-threaded server, but you talk about processes and not threads.

Each connection to a db implies two extra processes:

1 - A client process; this may or may not be on the database server.

2 - A server process to talk between 1 and the database daemons.

Cargill's Corporate Web Site

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