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What size should redo log be?
Redo log file size Dell EMC recommends redo log group members sized between 512 MB to 2 GB for demanding OLTP systems. If the DBA is concerned that a larger redo log group will result in insufficient switching during non-peak period, the archive_lag_target parameter should be set to force periodic switching.
How do you find the frequency of a redo log switch?
Ideally redo log switch frequency should be 4-5 log switches per hour. If there is frequent log switches then check the size of redo logs and increase accordingly. V$LOG_HISTORY is used to check history of redo log generation in Oracle.
How do I know the size of my redo log block?
The easy way to find redo block size is to get trace of redolog and read that.
- Below one is done on solaris platform: Dump redolog:
- Now check generated trace (it will under the same location where alert log is present)
- So redolog block size in this database is of 512 bytes.
How do I find the current redo log file?
The V$LOGFILE view can be used to find the datafiles for the redo logs.
How often should I size my redo log files?
Here is a handy script that will show you the current sizes of your redo log files: The general rule-of-thumb is that you should size your redo log files so that they do not switch more frequently than twice per hour. Remember that a redo log switch also forced a checkpoint, and this can degrade the performance of your database.
How does redo log work in Oracle Database?
Oracle Database assigns each redo log file a new log sequence number every time a log switch occurs and LGWR begins writing to it. When the database archives redo log files, the archived log retains its log sequence number. A redo log file that is cycled back for use is given the next available log sequence number.
How can I reduce the redo log generation?
In order to reduce the redo log generation, DBAs can increase the main memory cache size, one should also increase the commit frequency to reduce the disk i/o. However, for the faster i/o, DBAs can add more disk chains, for an economic solution, if cost is not the factor then it is suggested to use SSD disks.
What happens if redo log file is corrupted?
A redo log file might become corrupted while the database is open, and ultimately stop database activity because archiving cannot continue. You can set FORCE LOGGING and NOLOGGING at various levels, such as for a database, pluggable database (PDB), tablespace, or database object.
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