ksfdstblkini : skgfrgblkdev

Bug 13510853  Linux: Slow DB startup with many files due to DBW time in skgfrgblkdev()


Product (Component)Oracle Server (Rdbms)
Range of versions believed to be affected(Not specified)
Versions confirmed as being affected
Platforms affected
  • Linux X86-64bit

 It is believed to be a regression in default behaviour thus:
   Regression introduced in


This issue is fixed in


Related To:


Some customers on the release of Oracle on Linux x86-x64 may see
symptoms of slow database start up.  Supporting diagnostics such as strace
show a high number of accesses on /proc/diskstats.  The customer database 
also typically will have a high number of data files associated with it.
The root cause of the problem is the introduction of some new internal 
stats collection in which, in certain larger storage 
configurations exhibit suboptimal performance. 
The fix provided in this bug implements a means for customers to disable
this code path by defining an event in their init.ora/spfile (prior to 
database start up. 
Rediscovery Notes:
 If you experience symptoms of slow database start up, strace diagnostics 
 collected on the oracle processes such as a dbwr show a high number of 
 accesses on /proc/diskstats, and you have a large number of datafiles that 
 are part of your database, you may be encountering this issue.  
 Note that the new internal stats collection that is root cause of this issue 
 is only present in or later releases and only on the Linux ports of 
 the Oracle Server.
 Stacks of DBW process is likely to show lots of time in/under skgfrgblkdev
 eg: Example stack:
    skgfrgblkdev <- ksfdstblkini <- ksfdfstini <- ksfdopn1 
       <- ksfdopn <- kcfbid <- kcfida ...
 None other than reduce the number of DB datafile significantly
 This fix is disabled by default in onwards .
 To avoid the skgfrgblkdev calls in onwards set event 10298 
   level 3489660928 (0xd0000000)

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