| LNS wait on SENDREQ+ARCH wait on SENDREQ on ASYNC dataguard at primary database [message #630655] |
Fri, 02 January 2015 00:01  |
ashishkumarmahanta80
Messages: 231
Registered: October 2006
Location: kolkatta
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Senior Member |
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Dear All,
Today's AWR pointed out wait event as " log file sync" in OLTP.
Top 5 Timed Foreground Events
Event Waits Time(s) Avg wait (ms) % DB time Wait Class
DB CPU 3,294 74.83
direct path read 75,429 459 6 10.42 User I/O
db file sequential read 158,485 368 2 8.35 User I/O
log file sync 122,798 232 2 5.27 Commit
TCP Socket (KGAS) 14 30 2113 0.67 Network
Below are the configuration -
log_archive_config DG_CONFIG=(TAGICPRD, TAGICODS, TGDROLTP, TGDRODS)
log_archive_dest_1 location=+OLTP_DATA2/arc_oltp/ VALID_FOR=(all_LOGFILES, ALL_ROLES) DB_UNIQUE_NAME=TAGICPRD
log_archive_dest_2 SERVICE=TAGICODS LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES, PRIMARY_ROLE) DB_UNIQUE_NAME=TAGICODS
log_archive_dest_3 LOCATION=+OLTP_DATA2/arc_logicalods VALID_FOR=(STANDBY_LOGFILES, STANDBY_ROLE) DB_UNIQUE_NAME=TAGICPRD
log_archive_dest_4 SERVICE=TGDROLTP LGWR ASYNC NET_TIMEOUT=180 VALID_FOR=(ONLINE_LOGFILES, PRIMARY_ROLE) DB_UNIQUE_NAME=TGDROLTP
log_archive_dest_5 SERVICE=TGDRODS LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES, PRIMARY_ROLE) DB_UNIQUE_NAME=TGDRODS
Why the below events are appearing, though we have LGWR ASYNC?
Wait Event Histogram Detail (4 min to 1 hr)
Units for Total Waits column: K is 1000, M is 1000000, G is 1000000000
Units for % of Total Waits: m is 64*1024 milliseconds (approximately 67 seconds or 1.1 minutes) h is 4096*1024 milliseconds (approximately 70 minutes or 1.17 hours)
% of Total Waits: total waits for all wait classes, including Idle
% of Total Waits: value of .0 indicates value was <.05%; value of null is truly 0
Ordered by Event (only non-idle events are displayed)
% of Total Waits
Event Waits 4m to 1h <2m <4m <8m <1/4h <1/2h < 1h >=1h
ARCH wait on SENDREQ 1 99.5 .5
LNS wait on SENDREQ 1 100.0 .0
In our DR location, there is network issue. It was confirmed by oracle support team. So is that would be the issue, the above wait events appearing on primary OLTP?
We have implemented cascading data guard concept.
Waiting for your kind reply on the same...
Regards,
Ashish Kumar Mahanta
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| Re: LNS wait on SENDREQ+ARCH wait on SENDREQ on ASYNC dataguard at primary database [message #630659 is a reply to message #630658] |
Fri, 02 January 2015 04:08  |
ashishkumarmahanta80
Messages: 231
Registered: October 2006
Location: kolkatta
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Senior Member |
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Dear Michel,
Top 5 Timed Foreground Events
Event Waits Time(s) Avg wait (ms) % DB time Wait Class
DB CPU 3,294 74.83
direct path read 75,429 459 6 10.42 User I/O
db file sequential read 158,485 368 2 8.35 User I/O
log file sync 122,798 232 2 5.27 Commit
TCP Socket (KGAS) 14 30 2113 0.67 Network
Wait Event Histogram Detail (4 min to 1 hr)
Units for Total Waits column: K is 1000, M is 1000000, G is 1000000000
Units for % of Total Waits: m is 64*1024 milliseconds (approximately 67 seconds or 1.1 minutes) h is 4096*1024 milliseconds (approximately 70 minutes or 1.17 hours)
% of Total Waits: total waits for all wait classes, including Idle
% of Total Waits: value of .0 indicates value was <.05%; value of null is truly 0
Ordered by Event (only non-idle events are displayed)
% of Total Waits
Event Waits 4m to 1h <2m <4m <8m <1/4h <1/2h < 1h >=1h
ARCH wait on SENDREQ 1 99.5 .5
LNS wait on SENDREQ 1 100.0 .0
Other Wait events are conveyed to application team for tuning of sqls. This is the wait event whose root cause to find out.
Is it because, primary database is sending archive logs to standby and due to network issue at other end, generates wait?
Regards,
Ashish
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