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Mar 26, 2009 at 07:08 PM

I/O Wait on LogWriter

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Hi ,

We are inserting 500K rows into a table and process is taking so long. I think some of the parameters were not set correctly.

I can see a task status LogIOWait (LogQueue:UserTaskEOTReady) on this process and very few savepoints were issued even the log is filling up.

Below numbers are increasing while the processig is running as I believe there were few savepoints issued to write to data area.

Log Pages written 163,000

Waiting for Log writer 145,300

LogIOClusterSize = 8

LogQueueSize=3000

MaxSavepointTimeInterval 600

dbmcli on xdb>info log

OK

END

Name | Value

Log Mirrored = NO

Log Writing = ON

Log Automatic Overwrite = OFF

Max. Size (KB) = 8292096

Backup Segment Size (KB) = 2796200

Used Size (KB) = 1619952

Used Size (%) = 20

Not Saved (KB) = 1619952

Not Saved (%) = 20

Log Since Last Data Backup (KB) = 0

Savepoints = 73

Checkpoints = 0

Physical Reads = 0

Physical Writes = 162252

Queue Size (KB) = 24000

Queue Overflows = 851

Group Commits = 0

Waits for Logwriter = 145903

Max. Waits = 1

Average Waits = 0

OMS Log Used Pages = 0

OMS Min. Free Pages = 0

Please through some guidance on improving the process more efficient.

DB Version : 7.7.06.10 on Linux 64 bit.

Thanks

Naveen