Kbase P114586: Explanation of the _Latch table
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
24/03/2006 |
|
Status: Unverified
GOAL:
Explanation of the _Latch table
GOAL:
What kind of information is stored in the _Latch VST table
FIX:
The _Latch VST table contains statistics when using Progress proprietary algorithm to acquire a lock to shared resources (commonly used when setting the -spin parameter on multiprocessor systems).
_Latch-Lock is the number of times the latch has been successfully locked. It is an indication of how frequently the internal data structure regulated by the latch is being referenced.
_Latch-Hold is the connection number of the current latch holder if the latch is locked. This information is of no value at all and should be ignored.
_Latch-Busy is the number of times that a lock acquisition attempt found the lock busy because it was locked by another connection. The ratio of busy to locks is a rough indication of the amount of contention for the internal data structures regulated by the latch.
_Latch-Spin is the number of spinlock retry loop iterations that have been executed while trying to acquire the lock. This value is a very rough measure of how long a connection has to wait when there is contention.
_Latch-Wait is the number of times that a lock acquisition attempt had to wait (by sleeping) because the latch was already locked by another connection and it was still locked when the spin retry count was exhausted. The wait time is doubled for each successive wait, starting with 10 milliseconds, up to a maximum of five seconds after which it is not increased further. This value is a measure of how often the spin count has been exhausted.