Databases Reference
In-Depth Information
If we have experienced a high value for the
latch
free
event—we know that the value is high
if we encounter a latch free event in the top timed events in a statspack or AWR report—we
need to investigate the causes for latch contention in our database.
We can do this by querying the
V$LATCH
dynamic performance view. In step 3 we
query for information about willing-to-wait latches, obtaining the results shown in the
following screenshot:
In the example results, we can see that there is a high wait time (and some misses and
sleeps) for shared pool latches, so we can identify the area of the database that needs
to be tuned.
In step 4 we query the same dynamic performance view as above, this time investigating
immediate latch requests.
