Re: oracle database-startup time
Date: Mon, 22 Nov 2010 13:32:02 -0800 (PST)
Message-ID: <23f1dcec-60b4-4d85-bc01-a27a55195b76_at_j1g2000vbl.googlegroups.com>
On Nov 21, 3:25 pm, alex123 <michalw..._at_poczta.fm> wrote:
> Hi,
>
> I wanted to know what oracle database startup time depends on? Does
> size of database matter or it is constant on the same machine?
Size of the database matters only in the number of data files allocated to house the database data may increase with size and on startup Oracle has to read every file header block and compare the SCN information in it to the information in the Control file to verify the database is ready to be opened and does not require recovery. So dealing with 64 files should be faster than 512 files however when you can to do 2000 - 25000 IO per second depending on hardware you may not really notice.
The size of the online redo log files and the undo tablespaces also may have some bearing in that bigger logs could require more time to read to reapply activity in the event of crash recovery. Larger undo tablespaces would imply large transaction support (or heavy user load) that in turn could require more time to rollback incomplete work as part of the crash recovery processing (apply redo then undo incomplete transactions).
The size of the SGA matters in that allocating and loading control information into a large SGA may take longer than allocating a more moderate size SGA though this is usually not significant.
I would hazard to say that Startup time is mostly depending on the quality of the hardware.
HTH -- Mark D Powell -- Received on Mon Nov 22 2010 - 15:32:02 CST