Re: redo log stats

Technically it is a wait for space in the buffer, but one of the reasons why the buffer runs out of space is because a redo log switch is occuring, and the time taken too switch is so long (a few seconds perhaps) that the redo buffer fills before the switch is complete.

If the number of space requests is about the same as the number of log switches you don't have a problem. If it is vastly higher, then you may have to consider changing the log buffer size.

--
Jonathan Lewis
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Mr Taki wrote in message ...


>Hi all,

>I've seen conflicting "facts" regarding the Oracle statistic called

>'redo log space requests' and what actions to take to resolve the problem.

>Some say it pertains to waiting for redo log buffer space (in SGA) and some

>say to waiting for redo log file space (file), each with different actions.

>(Btw, my "gut" tells me that it is the latter, i.e. waiting for a complete

>log

>switch so that the next file/group can be used. But then I can think of a

>few different problems causing this, like too small files, or DBWR

>performance problem.)

>

>Can somebody bring forth explanation to the actual fact, whether it is the

>redo log file or the log buffer, and some source reference then I'd be

>really glad :-)

>

>Regards

>/Fad

>

>