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Home -> Community -> Mailing Lists -> Oracle-L -> Re: Cache a table
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 retired):
"Look, listen, and learn, for an original mistake is as rare as an original idea."
on 10/22/03 1:19 PM, Pete Sharman at peter.sharman_at_oracle.com wrote:
> 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 8:40 AM > To: Multiple recipients of list ORACLE-L > > > 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:
>>> Before Oracle 8 and the new touch count algorithm the cache
>>> 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
>>> be aged out immediately, quite possibly by itself if it consisted
>>> more than ~ db_file_multiblock_read_count blocks, i.e. the 2nd or
>>> full scan read would already override the previously read blocks. >>> Marking the table as CACHEd prevented that. >>> >>> At 01:09 PM 10/21/2003, you wrote: >>>> I always wondered why Oracle thought this was a useful table >>>> attribute. >>>> >>>> My gut feeling is that it is an extra that does little. >>>> >>>> For example, say we want to keep a code table in memory because it >>>> is constantly being hit for column verifiction. By definition, if >>>> a table is >>>> constantly being queried, it's segments will be in memory because >>>> they never >>>> age out. That sounds like cacheing to me. >>>> >>>> And then I remember a specific piece of Oracle documentation
>>>> that, >>>> even though we may mark a table to be "cached", it *still* may be >>>> aged out if memory is needed for other data blocks. >>>> >>>> Like I said, sounds a little like "here you have it, and here you >>>> don't". >>>> >>>> I'm sure that my impression is wrong and someone will correct me.
>>>> But I >>>> doubt I will use the "CACHE" option anytime soon. >>>> >>>> Tom Mercadante >>>> Oracle Certified Professional >>> >>> Wolfgang Breitling >>> Oracle7, 8, 8i, 9i OCP DBA >>> Centrex Consulting Corporation >>> http://www.centrexcc.com >>> >>> -- >>> Please see the official ORACLE-L FAQ: http://www.orafaq.net >>> -- >>> Author: Wolfgang Breitling >>> INET: breitliw_at_centrexcc.com >>> >>> Fat City Network Services -- 858-538-5051 http://www.fatcity.com >>> San Diego, California -- Mailing list and web hosting
>>>
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> > Mladen Gogala > Oracle DBA > > > > Note: > This message is for the named person's use only. It may contain > confidential, proprietary or legally privileged information. No > confidentiality or privilege is waived or lost by any mistransmission. If > you receive this message in error, please immediately delete it and all > copies of it from your system, destroy any hard copies of it and notify the > sender. You must not, directly or indirectly, use, disclose, distribute, > print, or copy any part of this message if you are not the intended > recipient. Wang Trading LLC and any of its subsidiaries each reserve the > right to monitor all e-mail communications through its networks. Any views > expressed in this message are those of the individual sender, except where > the message states otherwise and the sender is authorized to state them to > be the views of any such entity.
-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Tim Gorman INET: tim_at_sagelogix.com Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- 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 Wed Oct 22 2003 - 21:09:34 CDT
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