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dataguard中的特殊後臺程式及等待事件

2008-05-22 17:32

這些內容在官方文件Oracle® Data Guard Concepts and Administration都能找到
沒有翻譯，湊合看吧

1. 程式：

RFS：remote file server
On the standby system, the remote file server (RFS) receives redo data over the network from the
LGWR process and writes the redo data to the standby redo log files.

LNSn:
On the primary database, the LGWR process submits the redo data to one or more network server
(LNSn) processes, which then initiate the network I/O in parallel to multiple remote destinations.

MRP:managed recovery process
The managed recovery process (MRP) applies archived redo log files to the physical standby database,
and automatically determines the optimal number of parallel recovery processes at the time it starts.
The number of parallel recovery slaves spawned is based on the number of CPUs available on the
standby server.

LSP:logical standby process
The logical standby process (LSP) uses parallel execution (Pnnn) processes to apply archived redo
log files to the logical standby database, using SQL interfaces.

2.Wait events

2.1 ARCn Process Wait Events

The wait events that monitor the time it takes to spawn or delete RFS connections and to send the redo data to the standby database when using ARCH for the transport mode

2.1.1 ARCH wait on ATTACH
All ARCn processes to spawn an RFS connection.

2.1.2 ARCH wait on SENDREQ
All ARCn processes to write the received redo data to disk as well as open and close the remote archived redo log files.

2.1.3 ARCH wait on DETACH
All ARCn processes to delete an RFS connection.

2.2 LGWR SYNC Wait Events

The wait events that monitor the time it takes for the LGWR process on the primary database to:
    Complete writing to the online redo log files on the primary database
    Transmit the redo data to the remote standby destination
    Wait for the redo data to be written to the standby redo log files
    Receive acknowledgment from the remote standby destination

2.2.1 LGWR wait on LNS
The LGWR process waiting to receive messages from the LNSn process.

2.2.2 LNS wait on ATTACH
All network servers to spawn an RFS connection.

2.2.3 LNS wait on SENDREQ
All network servers to write the received redo data to disk as well as open and close the remote archived redo log files.

2.2.4 LNS wait on DETACH
All network servers to delete an RFS connection.

2.3 LGWR ASYNC Wait Events

The wait events that monitor the time it takes to write the redo data to the online redo log files on the primary database.

2.3.1 LNS wait on DETACH
All network servers to delete an RFS connection.

2.3.2 LNS wait on ATTACH
All network servers to spawn an RFS connection.

2.3.3 LNS wait on SENDREQ
All network servers to write the received redo data to disk as well as open and close the remote archived redo log files.

2.3.4 True ASYNC Control FileTXN Wait
The LNSn process to get hold of the control file transaction during its lifetime.

2.3.5 True ASYNC Wait for ARCH log
The LNSn process waiting to see the archived redo log (if the LNSn process is archiving a current log file and the log is switched out).

2.3.6 Waiting for ASYNC dest activation
The LNSn process waiting for an inactive destination to become active.

2.3.7 True ASYNC log-end-of-file wait
The LNSn process waiting for the next bit of redo after it has reached the logical end of file.

oracle dg後臺程式及wait event--轉載-精

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