Redo log member and control files at Oracle DB Standard Edition

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I am planing to dive into the oracle database world. Since the oracle database is such a complex machine, I want to inform myself as good as possible, before I start. I have some questions.

How many redo log members for each group can I define and how many control files can I use by using the standard edition (one)?

I've read, that I can have only two archive log destinations defined by LOG_ARCHIVE_DEST and LOG_ARCHIVE_DUPLEX_DEST in the standard edition (one). Now I am wondering, if there is any limitation by multiplexing redo log members and control files by using the standard edition (one) ?

I couldn't find this information except, that there can be 8 control files at all.

Best Answer

How many redo log members for each group can I define?

Database Limits

MAXLOGMEMBERS

Default: 2
Maximum Value : 5

How many control files can I use by using the standard edition (one)? I couldn't find this information except, that there can be 8 control files at all.

That is correct. CONTROL_FILES

Range of values:1 to 8 filenames

I've read, that I can have only two archive log destinations defined by LOG_ARCHIVE_DEST and LOG_ARCHIVE_DUPLEX_DEST in the standard edition (one).

LOG_ARCHIVE_DEST and LOG_ARCHIVE_DUPLEX_DEST are deprecated long ago. LOG_ARCHIVE_DEST_N is available since 8.1 in EE, and 10.1 in SE. You can define up to 31 destinations, but only the first 10 can be local. Remote destinations are not supported in SE.

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Recover oracle 10g database from old data files

Try to "recover until SCN..." before doing "open resetlogs".

You'll need the online redo logs to perform this (not clear from your question whether you have them or not)

Determine redo log size, number of redo log files

The recommendation is to have log switches occur a few times an hour. If you have a 100 log switches an hour with 50MB redo logs, you need e.g 1GB redo logs for 5 log switches/hour. 100*50 MB redo/hour for a 6.5GB database is unusually much though.

You can add the new logs, e.g:

ALTER DATABASE ADD LOGFILE THREAD 1 SIZE 1G;
ALTER DATABASE ADD LOGFILE THREAD 1 SIZE 1G;
ALTER DATABASE ADD LOGFILE THREAD 2 SIZE 1G;
ALTER DATABASE ADD LOGFILE THREAD 2 SIZE 1G;

Then force log switches until the new logs are used (CURRENT status) and old logs become ACTIVE/INACTIVE by:

ALTER SYSTEM SWITCH LOGFILE;

Then drop the old logs:

ALTER DATABASE DROP LOGFILE GROUP 1;
ALTER DATABASE DROP LOGFILE GROUP 2;
ALTER DATABASE DROP LOGFILE GROUP 3;
ALTER DATABASE DROP LOGFILE GROUP 4;

If you can't drop a logfile group because it is ACTIVE, do

ALTER SYSTEM CHECKPOINT;

so it becomes INACTIVE and try again.

Best Answer

Related Solutions

Recover oracle 10g database from old data files

Determine redo log size, number of redo log files

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