Examine the details of the Top 5 Timed Events in the following Automatic Workloads Repository (AWR) report: 
What are three possible causes for the latch-related wait events?
A.
The size of the shared pool is too small.
B.
Cursors are not being shared.
C.
A large number COMMITS are being performed.
D.
There are frequent logons and logoffs.
E.
The buffers are being read into the buffer cache, but some other session is changing the
buffers.
Explanation:
A,B are correct (rf. http://practical-tech.blogspot.fr/2012/10/how-to-tune-shared-pool-cache.html)
Not sure about E? any idea?
E is not correct – it’s for buffer busy waits
I would choose ABD
ABD also because new logon may generate new parses
Both latch: row cach objects & latch: shared pool indicate that there is
some issue with shared pool (latch contention).
“Row cache objects” is a latch which is used to protect the access to
data dictionary cache in the SGA.
A high value for this may indicate the following things.
1) There is excessive use of data dictionary information.
2) There is lot of hard parsing.
General solution to this problem is to increase the size of shared pool.
Latch: shared pool
Shared pool latch is used to protect memory allocation.
shared pool latch contention may indicate the following:
1) There is excessive hard parsing because the application is using literals
instead of bind variables.
2) Cursors are not being shared.
So based on that
++++++++++
A B D
++++++++++