LOG_BUFFER specifies the amount of memory (in bytes) that Oracle uses when buffering redo entries to a redo log file.

Property Description

Parameter type

Big integer

Default value

2 MB to 32 MB, depending on the SGA size and CPU count



Modifiable in a PDB


Range of values

2 MB to operating system-dependent



Redo log entries contain a record of the changes that have been made to the database block buffers. The LGWR process writes redo log entries from the log buffer to a redo log file.

The log buffer size depends on the number of redo strands in the system. One redo strand is allocated for every 16 CPUs and has a default size of 2 MB. Oracle allocates a minimum of 2 redo strands per instance. When the log buffer size is not specified, any remaining memory in the redo granules is given to the log buffer.

See Also:

  • Your operating system-specific Oracle documentation for the default value and range of values

  • Oracle Database Performance Tuning Guide for information on resizing the redo log buffer using this parameter