ARCH wait on SENDREQ 等待事件

ARCH wait on SENDREQ
Cause
High ARCH wait on SENDREQ wait events found in statspack report.


"ARCH wait on SENDREQ" -- This wait event monitors the amount of time spent by
all archiver processes to write the received redo data to disk as well as open
and close the remote archived redo log files.This wait events can lead to a slow performance.


1)It means that there is a slow network between primary and standby database.         -- 主備網路延遲比較大
2)It also means that there is a chance of slow performance on disk where remote       --調整下磁碟
archiving is happening.


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Solution
To implement the solution, please execute the following steps:   --按照下面步驟進行排查


1.Please get in touch with your network admin and check the network response.
2.If the remote destination is slow and archiver is taking longer to archive to
that destination, then the user needs to allocate more redo log groups so that
there is a logfile available for a logswitch to switch into, and not wait for
the archiver to finish archiving to the destination.
3.One more workaround you can use is to set below parameter in primary site:


_LOG_ARCHIVE_CALLOUT='LOCAL_FIRST=TRUE'






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.