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Home -> Community -> Usenet -> c.d.o.server -> Re: 10046 trace: 'latch free' then 'db file seq. read' waits
Spendius wrote:
> Hi,
> When you find a series of 'latch free' waits with p2=66 in a 10046
> trace file that are immediately followed by a 'db file sequential read'
>
> wait (and then again 'latch free' p2=66 lines until another 'db file
> seq. read' line with different file#/block# values etc etc.) does it
> mean that Oracle now shows a wait for a seq. read on this very
> p1=file# and p2=block# on which it was trying to get a 'cache buffer
> chain' latch a second before ?
>
> (to me the answer is yes but... one never knows)
>
> Thanks.
> Sp
>
Latch# 66 is this:
SQL> select name from v$latch where latch#=66;
NAME
SQL>
KJCT is a RAC communication layer. That latch wait means that before
each read, Oracle is checking minor and unimportant things like whether
the block is locked by another instance, which instance has the most
current version and alike. The only way to get rid of that latch is to
get rid of RAC.
Is there a problem? What is the most extensive wait you encounter? If
that is the most extensive wait, then there is a bug in your database
software and you should tell Oracle all about it ASAP.
-- Mladen Gogala http://www.mgogala.comReceived on Tue Jun 13 2006 - 11:08:22 CDT
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