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,E
A,B,D correct.
for C:
DC_USERS
This may occur if a session issues a GRANT to a user, and that user is in the process of logging on to the database.
взято тут: Issues For “Row Cache Lock” (Doc ID 1476670.1)
sorry…
for D:
DC_USERS
This may occur if a session issues a GRANT to a user, and that user is in the process of logging on to the database.
взято тут: Issues For “Row Cache Lock” (Doc ID 1476670.1)
ABE
A B and E appears to be correct.
ABD
http://docs.oracle.com/database/121/TGDBA/pfgrf_instance_tune.htm
Latch
=====
Shared pool, library cache
Possible Causes
===============
Lack of statement reuse
Statements not using bind variables
Insufficient size of application cursor cache
Cursors closed explicitly after each execution
Frequent logins and logoffs
Underlying object structure being modified (for example truncate)
Shared pool too small
ABD
ABD
Shared pool, library cache
Shared Pool
Possible Cuses for Latch Wait Events:
Lack of statement reuse
Statements not using bind variables
Insufficient size of application cursor cache
Cursors closed explicitly after each execution
Frequent logins and logoffs
Underlying object structure being modified (for example truncate)
Shared pool too small
Answers: A,B,D
ABD
ABD
Its ABE
ABE
ABE