Identify two placeholder wait events that can be observed while a session is waiting to access a block. (Choose two.)
A.
gc cr block busy
B.
gc current block request
C.
gc current block busy
D.
gc cr block request
E.
gc current grant busy
F.
gc cr grant busy
Correct: A, C
BC
gc current/cr request: These wait events are relevant only while a gc request for a cr block or current buffer is in progress. They act as placeholders until the request completes.
Sorry, I meant B, D.
Agree
B,D : correct
The process send message to LMS to access a block. The process must wait for LMS response. The process will wait on a placeholder event such as gc current request and gc cr request.
B,D but why not C???
For example, when a session on an instance is looking for a block
in the global cache, it does not know whether it will receive the
data cached by another instance or whether it will receive a message
to read from disk. The wait events for the global cache now convey
precise information and waiting for global cache blocks or messages is:
waiting for global cache blocks or messages is:
•Temporarily represented by a placeholder event which is
active while waiting for a block, for example:
◦gc current block request
◦gc cr block request
•Attributed to precise events when the outcome of the request is known, for example:
◦gc current block 3-way
◦gc current block busy
◦gc cr block grant 2-way