regarding the size of control file

[vijaya...@gmail.com]

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 .

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.

[fitzj...@cox.net]

Comments embedded.

vijaya...@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

[yon...@yahoo.com]

fitzj...@cox.net wrote:
> 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.

In spite of the names, maxlogfiles is the limit of log file groups, not
log files, and maxlogmembers is the limit of logfile members per group,
not for the entire database. Even though all documentation including 8i
SQL Reference says so, maxloghistory is for non-RAC or OPS as well, as
implied by Note:237413.1 and Note:1060139.6. (But the two notes give an
impression that maxloghistory sets the limit for logfiles or logfile
members, instead of logfile groups as documentation clearly says.)

Yong Huang