Re: What is Oracle doing during statup?

Can anyone tell me what Oracle does when it starts up? I'm particularly asking as I want to know why Oracle 8 on Solaris is taking around 10 minutes just to start the instance I've just extracted from a customers backup tape. Regards, Graeme

A couple of questions if I may --

Is this a cold or hot backup?

Cold backup.

How large is the database?

About 6 gig

Answers to these questions will help determine why the startup takes a while.  Now, on to what Oracle does during startup:

Oracle begins by allocating sufficient memory to house all of the required structures (SGA, PGA, UGA, buffers, etc.) and setting various parameters from the init.ora file, i.e., start archive logging, set a utl_file directory and so forth.  The figures reported on the console reflect these settings.

Next Oracle accesses the control files listed in the init.ora file and populates the various views/tables with data file information.  [If the control files are not readable the database will not mount and new control files will need to be created.]  It also assesses the need for recovery based upon the latest checkpoint in the control file and the latest recorded checkpoint in each data file.  The database is then mounted.

Oracle finally verifies the data files and starts any recovery operations necessary to bring them into line with the recorded checkpoints in the control files; this can take some time if this was a hot backup and the files are numerous and large.  Once the recovery is completed the database is opened.

This is by no stretch of the imagination a thorough discussion of the intricacies of the startup process, however it should give you a good idea of what is going on and why it may take a bit of time to actually get an instance up and running.

Thanks.
After running for 10 minutes it gives the error ORA-00205: error in identifying controlfile.
The alert file contains ORA-205 signalled during: alter database mount...

The datafile is present and has the correct permissions. The only 'non-normal' thing that's going on is that it's been accessed via symbolic links rather than normal directories - this wouldn't cause a problem would it?

Cheers,

Graeme Received on Wed Mar 13 2002 - 09:00:23 CST