[mailto:[EMAIL PROTECTED]
Sent: Wed 12/31/2003 6:34 PM
To: Multiple recipients of list ORACLE-L
Cc:
Subject: Re: Cache a table
Hi Richard,
Did you test the effect of Nocache after caching ?
What we noticed is cache followed by nocache is
not
making the blocks to be flushed out
Ravi Kulkarni [EMAIL PROTECTED]
Sent by: [EMAIL PROTECTED]
01/02/2004 07:59 AM
Please respond to ORACLE-L
To:Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
cc:
Subject:RE: Cache a table
That was what we expected. This is a highly active
PeopleSoft Database
recipients of list ORACLE-L
Cc:
Subject:RE: Cache a table
This thread started on 10/21/2003, with a *lot* of comments.
No time to read it all, so I'll just work with what appears here.
Have considered that this table is simply used a lot and remains
in the cache because it belongs there due
a portion of a post I
recently sent to
comp.databases.oracle.server in the Cache A Table
thread:
Simple demo on 9.2, the BOWIE table is approximately
13,000 blocks, SMALL is
117 blocks:
SQL alter table bowie nocache;
Table altered.
SQL select object_name, object_id, data_object_id
from
Message-
From: Ravi Kulkarni [mailto:[EMAIL PROTECTED]
Sent: Wed 12/31/2003 6:34 PM
To: Multiple recipients of list ORACLE-L
Cc:
Subject:Re: Cache a table
Hi Richard,
Did you test the effect of Nocache after caching ?
What we noticed is cache followed by nocache is not
making
a portion of a post I recently sent to
comp.databases.oracle.server in the Cache A Table thread:
Simple demo on 9.2, the BOWIE table is approximately 13,000 blocks, SMALL is
117 blocks:
SQL alter table bowie nocache;
Table altered.
SQL select object_name, object_id, data_object_id from
to
comp.databases.oracle.server in the Cache A Table thread:
Simple demo on 9.2, the BOWIE table is approximately 13,000 blocks, SMALL is
117 blocks:
SQL alter table bowie nocache;
Table altered.
SQL select object_name, object_id, data_object_id from dba_objects where
object
_name in ('BOWIE', 'SMALL
To:Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
cc:
Subject:Re: Cache a table
Hi
It depends on how you define an LRU list I guess. When I close my eyes and
picture the cache, I still see a LRU in there somewhere. Please note I don't
often close my eyes
I think you have mentioned that once or twice. :)
Pete
Controlling developers is like herding cats.
Kevin Loney, Oracle DBA Handbook
Oh no, it's not. It's much harder than that!
Bruce Pihlamae, long-term Oracle DBA
-Original Message-
Mladen Gogala
Sent: Wednesday, October 22, 2003
I have two favorite email signatures. One is used by Gary Dodge who is
commencing his 68th quarter at Oracle Corporation. It reads:
Building tomorrow's legacy systems today, one crisis at a time...
And the other is used by a gentleman named Gene Fosnight, formerly of Oracle
(now happily
Hi all,
when you would consider to put a table a cache...
rgds
gb
Want to chat instantly with your online friends? Get the FREE Yahoo!
Messenger http://mail.messenger.yahoo.co.uk
--
Please see the official ORACLE-L FAQ
Never. Altering the table to cache does not gurantee that it will be always
be available in the cache. It simply means the table will be placed in the
Least recently used end of the LRU list and it will age away as time goes
by, just like any other table.
A better approach is to use KEEP pool
ORACLE-L
Never. Altering the table to cache does not gurantee that it will be always
be available in the cache. It simply means the table will be placed in the
Least recently used end of the LRU list and it will age away as time goes
by, just like any other table.
A better approach is to use KEEP
when the table is
1] frequently accessed
2] relatively small
Regards
B S Pradhan
On Tue, 21 Oct 2003 Gunnar Berglund wrote :
Hi all,
when you would consider to put a table a cache...
rgds
gb
Want to chat instantly
Mike:
I guess we are aware there is no concept of LRU or MRU in current
versions of Oracle and I don't think CACHE option will influence the
behavior. With the new algorithm the MFU blocks are already in the hot
end (unless they are read using CR read in that case they will be in
cold end since
From 9.2 doc:
The LRU Algorithm and Full Table Scans
When the user process is performing a full table scan, it reads the blocks
of the table into buffers and puts them on the LRU end (instead of the MRU
end) of the LRU list. This is because a fully scanned table usually is
needed only briefly, so
...
Anyway, marking a table as CACHE and placing it in a KEEP buffer pool which
is large enough to accommodate all of the used blocks is the closest thing
to pinning a table into the Buffer Cache as you'll get, as Arup described.
Of course, there is little benefit from such a move, as Arup also
the instance and want the hit
ratio to look good :)
HTH.
Arup Nanda
- Original Message -
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Sent: Tuesday, October 21, 2003 3:39 AM
Hi all,
when you would consider to put a table a cache...
rgds
gb
mine and do
not reflect those of my employer or customers **
-Original Message-
From: Tim Gorman [mailto:[EMAIL PROTECTED]
Sent: Tuesday, October 21, 2003 6:59 AM
To: Multiple recipients of list ORACLE-L
Subject: Re: Cache a table
Good points, Arup.
Actually, I would argue
contained in this message are entirely mine and do
not reflect those of my employer or customers **
-Original Message-
From: Tim Gorman [mailto:[EMAIL PROTECTED]
Sent: Tuesday, October 21, 2003 6:59 AM
To: Multiple recipients of list ORACLE-L
Subject: Re: Cache a table
Good points, Arup
employer or customers **
-Original Message-
From: Tim Gorman [mailto:[EMAIL PROTECTED]
Sent: Tuesday, October 21, 2003 6:59 AM
To: Multiple recipients of list ORACLE-L
Subject: Re: Cache a table
Good points, Arup.
Actually, I would argue that there is better reason to
consider
Before Oracle 8 and the new touch count algorithm the cache attribute made
sense. If a small, frequently used table was read by a full scan, it would
have been put at the end of the LRU chain eligible to be aged out
immediately, quite possibly by itself if it consisted of more than ~
, October 21, 2003 6:59 AM
To: Multiple recipients of list ORACLE-L
Subject: Re: Cache a table
Good points, Arup.
Actually, I would argue that there is better reason to
consider using the
RECYCLE pool than to consider how to cache tables or
use the KEEP pool.
The advantage of effective
Did anyone try to benchmark the touch count based algorithm against
the old LRU list? LRU list had advantage of being intuitive, while
touch count algorithm is depending on many parameters for which I
don't exactly understand the impact. LRU list parameters were
essentially defining the desired
BTW, a good text to really understand the touch counts is found
here:
http://cslibrary.stanford.edu/105/LinkedListProblems.pdf
It's not oracle specific, but gives you a hint how do things work.
On 10/21/2003 05:14:28 PM, Mladen Gogala wrote:
Did anyone try to benchmark the touch count based
Title: RE: Cache a table
John,Tom,
There is a difference between pools {DEFAULT vs. KEEP and RECYCLE}.
By default only DEFAULT pool use mid-point insert. It is controlled by hidden parameters
_db_percent_hot_default (Percent of default buffer pool considered hot) default 50
Have a look at Steve Adam's web site. He probably knows more about it than
just about anyone else I know (as usual!)
Pete
Controlling developers is like herding cats.
Kevin Loney, Oracle DBA Handbook
Oh no, it's not. It's much harder than that!
Bruce Pihlamae, long-term Oracle DBA
Title: RE: Cache a table
Sure, Wolfgang. Thank you for the correction.
Alex.
-Original Message-
From: Wolfgang Breitling [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, October 21, 2003 2:54 PM
To: Multiple recipients of list ORACLE-L
Subject: RE: Cache a table
I suppose you mean 2
Good idea. I located the meaning of TIM column (time to age buffer).
BTW, did I tell you that I like your signature?
On 10/21/2003 05:39:25 PM, Pete Sharman wrote:
Have a look at Steve Adam's web site. He probably knows more about
it
than
just about anyone else I know (as usual!)
Pete
: Multiple recipients of list
ORACLE-LSubject: RE: Cache a table
John,Tom,
There is a difference between pools {DEFAULT vs. KEEP and
RECYCLE}. By default only DEFAULT pool use "mid-point"
insert. It is controlled by hidden parameters _db_percent_hot_default (Percent of default b
Title: RE: Cache a table
Mladen,
John Beresniewicz did some test (last one I know of in 2000 with Oracle 8.0) with diffent values of
_db_aging_cool_count
_db_aging_freeze_cr
_db_aging_hot_criteria
_db_aging_stay_count
_db_aging_touch_time
_db_percent_hot_default
_db_percent_hot_keep
I wonder how can I cache a table other than
creating it with the cache option.??
Bunyamin K.Karadeniz Database
Group / Information Systems Department HAVELSAN Ankara
/TURKEY Tel : +903122873565 / 1681
Mobile Tel : +90 535 3357729
alter
table table_name cache;
HTH
Mark
-Original Message-From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Bunyamin
K.KaradenizSent: Thursday, May 03, 2001 03:31To:
Multiple recipients of list ORACLE-LSubject: HOW TO CACHE THE
TABLE??
I wonder how can I
33 matches
Mail list logo
