KlausE
New Member
There are these two DB parameters: -groupdelay and -Mf
Group Delay (-groupdelay): 0-1000 ms, default is 1 for multi user
The number of milliseconds a transaction waits before committing. Use Group Delay (-groupdelay) to increase performance when Delayed BI File Write (-Mf) is set to zero.
Delayed BI File Write (-Mf): 0-32000sec, default 3 for multi user
Value in seconds of the delay before the database engine synchronously writes to disk the last before-image file records at the end of each transaction. It also specifies the interval that the broker process wakes up to make sure all BI file changes have been written to disk. The default is 3 for single-user batch jobs and for multi-user databases. Otherwise, the default is zero (0).
These parameters sound very similar to me. As -Mf is disabling -groupdelay by default, I assume -Mf is the newer and better one. -Mf is also seconds, not milliseconds so it can have a bigger impact.
But one customers says, that he has better single batch job performance with -Mf 0 and -groupdelay 1.
Can you tell me which is better or what is the difference in the mechanism?
thanks, Klaus
Group Delay (-groupdelay): 0-1000 ms, default is 1 for multi user
The number of milliseconds a transaction waits before committing. Use Group Delay (-groupdelay) to increase performance when Delayed BI File Write (-Mf) is set to zero.
Delayed BI File Write (-Mf): 0-32000sec, default 3 for multi user
Value in seconds of the delay before the database engine synchronously writes to disk the last before-image file records at the end of each transaction. It also specifies the interval that the broker process wakes up to make sure all BI file changes have been written to disk. The default is 3 for single-user batch jobs and for multi-user databases. Otherwise, the default is zero (0).
These parameters sound very similar to me. As -Mf is disabling -groupdelay by default, I assume -Mf is the newer and better one. -Mf is also seconds, not milliseconds so it can have a bigger impact.
But one customers says, that he has better single batch job performance with -Mf 0 and -groupdelay 1.
Can you tell me which is better or what is the difference in the mechanism?
thanks, Klaus