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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Oracle Internals
<FONT face=Arial color=#0000ff
size=2>....make that "V$LATCH" to find the SLEEP1-11
columns....
<FONT face="Times New Roman"
size=2>-----Original Message-----From: Mohan, Ross
[mailto:MohanR_at_stars-smi.com]Sent: Wednesday, March 14, 2001 9:06
AMTo: Multiple recipients of list ORACLE-LSubject: RE:
Oracle Internals
HP, it is sleep/wake/check. it is up to the process to acquire
the resource. AFAIK, there is no message-passing type
of algorithm to tell waiting (whether spinning or
sleeping) processes when the semaphore becomes unset (
ie the resource is available ) Sleeps are expensive in
Latchville, and you can track their occurence via
v$latch_waits and the SLEEP* columns.
hope this partial answer helps.
-----Original Message----- From: Henry
Poras [<A
href="mailto:Henry.Poras_at_ctp.com">mailto:Henry.Poras_at_ctp.com]
Sent: Tuesday, March 13, 2001 10:25 PM <FONT
size=2>To: Multiple recipients of list ORACLE-L <FONT
size=2>Subject: Oracle Internals
I have been rereading Steve Adam's book a bit more carefully
and have a question. Just wondering if anyone has any
answers.
When talking about latch sleeps, the book states "a process
sleeping for a latch waits on its semaphore". However,
latches don't support queuing and a number of
processes may be waiting for the same latch. If I am sleeping and
the latch frees, who knows I need that semaphore? Are all
waiting processes posted with the semaphores going
on/off/on/off? or is no semaphore posted and the
processes go sleep/wake/check/sleep/wake/check? I can't quite <FONT
size=2>picture the details here.
Henry
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