Some Latch Questions

From: Diego Cutrone <dcutrone_at_afip.gov.ar>
Date: Mon, 14 Aug 2000 16:02:19 -0300
Message-Id: <10589.114524@fatcity.com>

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Hi,

Forgive my poor english.
An Oracle 7.3.4 (AIX 4.3.3) database is suffering of some "latch = waits".

    Especially on "cache buffers lru chain " and some on "modify = parameter values"
=20
  What can I do about them?
  I think that the first latch is needed for the server processes in = order to
  gain access to the LRU list in the buffer cache. Contention there = means that there
  are a lot of processes that want free buffers.   I think it would help if I increase db_block_buffers parameter. am I = right?
  if not, What about increasing DBWR thoughtput ?

What does it mean the second latch? =20

Thanks.

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<DIV><FONT size=3D2>Hi,</FONT></DIV>
<DIV><FONT size=3D2>    Forgive my poor =
english.</FONT></DIV>
<DIV><FONT size=3D2>    An Oracle 7.3.4 (AIX 4.3.3) =
database is=20
suffering of some "latch waits".</FONT></DIV>
<DIV><FONT size=3D2>    Especially on "<FONT=20
face=3D"Courier New" size=3D2>cache buffers lru chain " and some on = "<FONT=20
face=3D"Courier New" size=3D2>modify parameter=20 values"</FONT></FONT></FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New" size=3D2><FONT =
face=3D"Courier New"=20
size=3D2>  </FONT></FONT></FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New" size=3D2><FONT =
face=3D"Courier New"=20
size=3D2>  What can I do about them?</FONT></FONT></FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New" size=3D2><FONT =
face=3D"Courier New"=20
size=3D2>  I think that the first latch is needed for the server = processes in=20
order to</FONT></FONT></FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New" size=3D2><FONT =
face=3D"Courier New"=20
size=3D2>  gain access to the LRU list in the buffer cache. = Contention there=20
means that there</FONT></FONT></FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New" size=3D2><FONT =
face=3D"Courier New"=20
size=3D2>  are a lot of processes that want free=20 buffers.</FONT></FONT></FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New" size=3D2><FONT =
face=3D"Courier New"=20
size=3D2>  I think it would help if I increase db_block_buffers = parameter. am=20
I right?</FONT></FONT></FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New" size=3D2><FONT =
face=3D"Courier New"=20
size=3D2></FONT></FONT></FONT><FONT face=3D"Courier New" size=3D2>  = if not, What=20
about increasing DBWR thoughtput ?</FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2></FONT> </DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New" size=3D2><FONT =
face=3D"Courier New"=20
size=3D2></FONT></FONT></FONT> </DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New" size=3D2><FONT =
face=3D"Courier New"=20
size=3D2>  What does it mean the second latch? =20
</FONT></FONT></FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New" size=3D2><FONT =
face=3D"Courier New"=20
size=3D2></FONT></FONT></FONT> </DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New" size=3D2><FONT =
face=3D"Courier New"=20
size=3D2>Thanks.</FONT></FONT></FONT></DIV></BODY></HTML> Received on Mon Aug 14 2000 - 14:02:19 CDT