Re: regarding the size of control file

Comments embedded.
vijaya.namala_at_gmail.com wrote:
> hi all,
>
>
> I have two doubts regarding the size of control file.
>
> 1. I know that the size of control file depends on MAXDATAFILES,
> MAXLOGFILES, MAXLOGMEMBERS, MAXLOGHISTORY, and MAXINSTANCES .I also
> know that the size of control file will increase automatically by
> adding more file than this .I have oracle 8i on windows NT .
>
> I watn to know , how this different parameters
> (MAXDATAFILES,MAXLOGFILES,MAXLOGMEMBERS etc) effect the size of control
> file.In the sense ,what is the contribution of each parameter for the
> size of control file . I want this to estimate the size of control file
> depending different number of different files .
>

You're missing an important parameter governing the size of your controlfiles: control_file_record_keep_time, which controls the number of reusable entries your controlfiles contain. By default it is set to 7; increasing this value also increases your controlfile size. The mazimum value for this parameter is 365, and the minimum value is 0.

As to the others you've mentioned:

maxdatafiles: set when the database or controlfile is created and controls the initial soze of the datafiles section. Adding more files expands this area until the limit specified by db_files is reached. The only way to increase this starting value is to re-create the controlfile or re-create the database.

maxlogfiles: the maximum number of redo log files which can ever be created for a database.

maxlogmembers: the maximum number of identical copies of a redo log allowed. The default and maximum values are operating system dependent.

maxloghistory: this is only valid in ARCHIVELOG mode for Real Application Clusters, as it governs the mazimum number of archived redo log groups to use for recovery in a RAC configuration. Outside of RAC it has no effect on controlfile size.

maxinstances: the maximum number of instances which can have a single database open at the same time. The minimum value is 1; default and maximum values are operating system dependent. Oracle provides no examples of changing the maxinstances parameter for a single database; I see no benefit of increasing this parameter value for a stand-alone database.

>
> 2.I found that , the maximum size of control file in windows is 20000
> blocks . Can anyone tell me what is the maximum size of control file in
> UNIX.
The size would be operating system dependent. A 64-bit operating system would allow a larger size than a 32-bit operating system. YOu wil need to check the operating system specific documentation for the version of UNIX you choose to run.

David Fitzjarrell Received on Thu Aug 04 2005 - 08:08:00 CDT