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Parallel Query Wait Events

原创 Oracle 作者:xzh2000 时间:2008-04-17 09:55:46 0 删除 编辑


This is intended as a reference for anyone involved in database tuning.

At the moment we consider the following PX wait events as idle:
- "PX Idle Wait"
- "PX Deq: Execution Msg"
- "PX Deq: Table Q Normal"
- "PX Deq Credit: send blkd"
- "PX Deq: Execute Reply"
- "PX Deq Credit: need buffer"
- "PX Deq: Signal ACK"
- "PX Deque wait"

[@more@]In 9i statspack does not filter out all idle PX wait event in
the Top 5 wait event section. So it can happen that you see
a PX idle wait event in this section.

The full list of Parallel Execution wait events are documented here
for completeness.

Parallel Execution Wait Events

Parallel Recovery
"PX Deq: Par Recov Reply"
"PX Deq: Par Recov Execute"
"PX Deq: Par Recov Change Vector"
"Replication Dequeue "
"waiting for slave message"

Parallel Query
"PX Deq: Table Q Normal"
Note 270921.1
"PX Deq: Table Q Sample"
"PX Deq: Table Q qref"
"PX Deq: Table Q Get Keys"
"PX Deq: Table Q Close"

Index Operations
"PX Deq: Merge Reply"
"PX Deq: Index Merge Execute"
"PX Deq: Index Merge Close"
General Parallel Execution
"PX qref latch"
Note 240145.1
"PX server shutdown"
Note 250357.1
"PX create server" obsolete since Oracle 8.0
"PX signal server"
"PX Deque wait"
"PX Idle Wait"
Note 257595.1
"PX Deq: Join ACK" Note 250960.1
"PX Deq Credit: need buffer" Note 253912.1
"PX Deq Credit: free buffer"
"PX Deq Credit: send blkd"
"PX Deq: Test for msg"
"PX Deq: Signal ACK"
Note 257594.1
"PX Deq: reap credit" Note 250947.1
"PX Nsq: PQ descriptor query"
"PX Nsq: PQ load info query"
"PX Deq: Msg Fragment"
Note 254760.1
"PX Deq: Parse Reply" Note 257596.1
"PX Deq: Execute Reply" Note 270916.1
"PX Deq: Execution Msg" Note 69067.1

Parallel Transaction Recovery
"PX Deq: Txn Recovery Start"
"PX Deq: Txn Recovery Reply"

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