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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Gets vs pins in v$librarycache
In a more simplified way yuo can say that:
GETS Shows the total number of requests for information on the
corresponding item and
PINS shows the number of times an item in the library cache was executed.
-----Original Message-----
From: yong huang [mailto:yong321_at_yahoo.com]
Sent: Friday, May 26, 2000 11:34 AM
To: Multiple recipients of list ORACLE-L
Subject: Gets vs pins in v$librarycache
Can somebody tell me the exact difference between the gets and pins in v$librarycache? The documentation for v$librarycache says:
gets: number of times a lock was requested for objects of this namespace
gethits: number of times an object's handle was found in memory
pins: number of times a PIN was requested for objects of this namespace
pinhits: number of times all of the metadata pieces of the library object
were
found in memory
Now, let's say the namespace is SQL Area. According to the above description plus these two pages:
http://x75.deja.com/getdoc.xp?AN=621820177&CONTEXT=959316014.2116878342&hitn
um=2
and
http://x75.deja.com/getdoc.xp?AN=624407275&search=thread&CONTEXT=959316014.2
116878342&HIT_CONTEXT=959316014.2116878342&hitnum=1
, my understanding is: gets is the number of times an oracle process tries
to
find if a particular SQL statement has been parsed before and left a "mark"
in
library cache, gethits means yes it has, pins is the number of times an
oracle
process tries to find all necessary data and code (text in UNIX's
terminology?), and pinhits is yes all necessary, ready-to-use data and
compiled
machine code are found, i.e. they're not flushed out of memory.
Please clarify. If this understanding is correct, I don't understand why the
library cache bothers to store just the "mark" or handle to the SQL
statement
if its parsed, ready-to-use machine code could have been flushed out
already.
Also I noticed that my pins is much greater, not smaller, than gets.
Yong Huang
yong321_at_yahoo.com
-- Author: yong huang INET: yong321_at_yahoo.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Mon May 29 2000 - 05:52:27 CDT
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