Re: Oracle under Unix

Can't answer all of your questions, anyway here goes

1 IPC stands for InterProcess Communication. All Oracle processes (whether server or client) directly communicate with each other instead of using TCP/IP. IPC is implemented in Unix by means of semaphores, which can be shown (together with shared memory segments, another means of IPC) by the ipcs command

2 resident set size: this should be the same as what is called working set in VMS. Only part of the memory required by a process is held in physical memory. This is called the resident set. Pages are faulted in or faulted out on demand.
Zero-fill pages: in many OSes it is customary whenever a process requests a new page (ie not retrieved from an image on disk) to store data, this new page is completely zeroed out.

Hth,

Sybrand Bakker, Oracle DBA

Reid Lai wrote:

> Hi there,
>
> Because I am not Unix expert, I have a few questions about some
> terminology and relationship with Oracle Database:
>
> 1. What does IPC mean? I also found a Unix command called ipcs. How
> IPC can affect Oracle instance?
>
> 2. Some information found in process trace file but don't understand
> completely:
> User time vs. System time
> Resident set size
> Zero-fill pages
> Voluntary vs. Involuntary context switches
> Don't understand why Logical Reads = 0 but Bytes from Logical reads
> gets 631.
>
> --
> Best Regards,
>
> Reid Lai <reidlai_at_hk.super.net>
> Oracle 7.3 Certified Database Administrator (OCP)
> ================================================
> The above opinions are mine and do not represent
> any official standpoints of my employer

Received on Mon Dec 28 1998 - 14:21:25 CST