Multiple Buffer Pools Feature

Have somebody used it and what are your comments?
I have very high activity for specific tables growing over 15-20 mnl of records. Many inserts and few select. very optimized SQL but still slower then the same code on DB2.
I would like to separate may be temp tablespace, and a few tables I never select from - like log and audit tables.
Will multiple Buffer Pools be beneficiary for me?
Thanks,

Thanks a lot - Yes, your assumption is absolutely right - the application always reports much higher time then I could see from the Oracle side even when I add all SQLNet waits. The same time on Db2 is approximatelly equal - again, the app reported time is a little bit higher, but it's not 250 times difference like in Oracle.
The app is 3rd party and get a lot of data in and out. The app structure is: Reading XML file and inserting the values in common tables like Address, Name, etc. As a next step the application will check if these records already exist and will perform specific logic if previous entries are found. From Oracle point these are multiple selects and few possible updates and/or inserts. After all processing is done a record in a log table will be inserted and the transaction is commited. Then the app gets the next XML record. This is single threaded process repeating over and over again. The capacity is about 25,000 records inserted per minute with about 40 application instances running simultaneously. if I increase the number of app instances running against DB2 to 100, the insert rate jumps to 60-65,000/min. In Oracle is the opposite - the increase of the app processes more then 45-50 do not change the insert rate at all. Even on SQL server I can run about 70 processes... So, something is wrong with the way Oracle process runs. These results are not new and have been run on at least 30 different hardware setups for months -AIX, linux, Solaris, windows, and on differnet type of hardware. This is the result for all of them. Everybody who tried the app reports the same case. Most of this cases though do not have well tuned environment... That's why I'm trying to make it work better - could not be "just doesn't run!!!" - Oracle is a great scalable system!
I've already thought to run the app locally on the server, but it's very hard as the usual set up takes about 3-4 hours and the app is very CPU consuming. But for a single app instance it'll work.
I think your idea is great and I must do it. Let me do that first thing on Monday and I'll post the results.
Thanks a lot,
mj

Similar Messages

  • MULTIPLE BUFFER POOL의 개념 및 사용 방법 (ORACLE8)

    제품 : ORACLE SERVER
    작성날짜 : 1999-05-13
    Multiple Buffer Pool의 개념 및 사용 방법
    1. 필요성
    table이나 index 등 segment는 그 사용 빈도나 중요도 등에 따라 memory에
    buffering되는 것을 달리 할 필요가 있다. Oracle8에서는 buffer cache에 대해서
    multiple buffer pool이라는 새로운 특성의 개념을 제공하여 segment마다 다른
    buffer를 사용할 수 있도록 하고 있다.
    multiple buffer pool은 'keep', 'recycle', 그리고 'default' buffer pool로
    구성되며, 이것을 control하기 위한 internal algorithm은 하나의 buffer pool을
    사용할 때와 대부분 마찬가지다. 즉, 기존의 CACHE option이나 full table scan 시
    LRU end에 위치시키는 것 등은 모두 변함이 없으며, 단지 그러한 기법들이 각
    buffer마다 별도로 적용된다는 것 뿐이다.
    2. buffer의 종류
    multiple buffer pool의 주요 목적은 서로 다른 형태로 사용되는 것을 나누어 놓
    아 서로 방해가 되지 않도록 하는 것으로 정리할 수 있으며, 각각 다음과 같은
    경우에 사용하도록 한다.
    (1) KEEP buffer pool : 가능한 한 memory에 오랫동안 유지되어져야 하는
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    전후의 크기를 가진 segment가 이 pool을 사용하기에 적당하다.
    그러나, 여기에서도 Oracle7.3의 CACHE option과 마찬가지로 새로이 access
    되는 segment에 의해 LRU end 쪽으로 이동하는 것이 가능하므로 항상 cache
    된다고 보장할 수는 없다.
    적당한 크기로 지정하는 것이 중요한데 당연히, 동시에 memory에 올려지기를
    바라는 object들의 크기의 합보다는 커야 한다.
    (2) RECYCLE buffer pool : 자주 사용되어지지 않거나, buffer pool의 두배보다
    큰 정도의 큰 segment가 index search를 하는 작업 등에 사용되어지도록 한다.
    (3) DEFAULT buffer pool : 위의 두 buffer pool에 할당되지 않은 나머지는
    default buffer pool이 된다. 그러므로 KEEP이나 RECYCLE buffer pool은
    없어도 반드시 default buffer pool은 존재하게 된다.
    이 buffer pool은 Oracle7의 하나의 buffer pool과 같다.
    3. buffer pool을 설정하는 방법
    이러한 종류의 buffer pool을 지정하기 위해서 BUFFER_POOL_KEEP과
    BUFFER_POOL_RECYCLE이라는 parameter가 존재하며, DB_BLOCK_BUFFERS
    와 DB_BLOCK_LRU_LATCHES parameter도 함께 고려하여야 한다.
    syntax는 다음과 같다.
    BUFFER_POOL_KEEP=(buffers:<value>,lru_latches:<value>) 혹은
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    BUFFER_POOL_RECYCLE=(buffers:<value>,lru_latches:<value>) 혹은
    BUFFER_POOL_RECYCLE=<value>
    위의 syntax에서 보는 바와 같이 각 pool에 대해서 buffer의 갯수 뿐 아니라
    LRU latch의 갯수도 지정할 수 있다. 만약 지정하지 않으면 그 pool에 대해서
    하나의 latch가 할당되는 것이다.
    DEFAULT pool에 대해서는 명시적으로 block의 갯수나 latch의 갯수를 지정할
    수 없고, 대신 전체 block의 갯수 (DB_BLOCK_BUFFERS)와 전체 LRU latch의
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    값을 뺀 것만큼 default pool에 할당된다.
    간단한 예제로 설명하면 다음과 같다.
    예를 들어 initSID.ora file에 다음과 같이 parameter가 설정되어 있다고 가정한다.
    DB_BLOCK_BUFFERS=1000
    DB_BLOCK_LRU_LATCHES=6
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    BUFFER_POOL_RECYCLE=100
    이러한 경우 KEEP pool에 대해서는 400개의 block과 2개의 LRU latch가 할당
    되고 RECYCLE pool에는 100개의 block과 1개의 LRU latch가 할당된다. 그리
    고 DEFAULT pool에는 500 (1000-400-100) 개의 block과 3 (6-2-1)개의 LRU latch
    가 할당되게 된다.
    각 LRU queue에 대해서 block은 균등하게 배분된다.
    즉, 이 예에서 DEFAULT queue는 LRU 1번이 167개의 block을 LRU2도 167개, 그리
    고 LRU3은 166개의 block을 가지게 되며, KEEP queue는 두개의 latch가 각각
    200개씩의 block을 그리고 RECYCLE queue는 100개의 block을 가지게 된다.
    이러한 정보는 v$buffer_pool을 통해 확인이 가능하며,
    이 예의 경우 다음과 같이 조회된다. 여기에서 set_count가 각 pool에 할당된
    latch의 갯수이며, lo_bnum과 hi_bnum이 buffer의 range이다.
    SQL> select * from v$buffer_pool;
    NAME      LO_SETID HI_SETID SET_COUNT BUFFERS LO_BNUM HI_BNUM
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    RECYCLE 6 6 1 100 400 499
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    같이 설정하면 alert.log file에 "Incorrect parameter specification for
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    4. buffer pool을 지정하는 방법
    BUFFER_POOL이라는 Oracle8에서 새로 추가된 storage 절의 parameter를 이용
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    이러한 통계 정보를 담고 있는 view는 v$buffer_pool_statistics이며,
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  • Buffer pool keep and multiple db block sizes

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  • Shall I use one datasource for multiple connection pool?

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  • No free buffers available in buffer pool default

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  • Default Buffer Pool Busy Waits and Default Buffer Pool Hit Ratio

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  • Db_keep_cache_size shows 0 when i keep object in KEEP buffer pool !

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  • Table in Keep Buffer Pool

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  • Clearing Data Buffer Pools

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  • Keep buffer pool after restart of the server

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    Donald K. Burleson
    Oracle Press author
    Author of "Oracle Tuning: The Definitive Reference"
    http://www.rampant-books.com/book_2005_1_awr_proactive_tuning.htm

  • Buffer pool Cache is two low .

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    > {quote:title=user640913 wrote:}{quote}
    > Thanks for the Response .
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    > ransactions:          6.70                                        0
    > [eBlocks changed per Read: 1.00 Recursive Call %: 70.83
    > Rollback per transaction %: 3.84 Rows per Sort: 103.67
    >
    Since you're licensed to run the AWR why are you bothering with something as silly as that SQL for the "buffer cache hit ratio" !
    You need to compare a "pre-problem" AWR with the current AWR reports to see if you can spot the changes that might be the significant ones, but based purely on the Load Profile that you have shown, you're not really doing much work, but you're doing it the hard way. The figures that stand out are:
    {code}
    Logical reads:           55,554.6                             8,285.20
    Physical reads:        15,842.52                              2,318.37
    {code}
    You can check the instance statistics to learn more about what type of read activity is generating these physical reads, and work out whether (a) it's sensible and (b) it's supportable on your number of disc. Having said that - take a look at the "SQL ordered by Reads" section of the report to see which SQL statements are responsible for most of the reads, get the historic plans from the AWR and then work out why the plan changed and how to produce a better plan.
    See my note below that explains why my quote of your results is tidier than your original.
    Regards
    Jonathan Lewis
    http://jonathanlewis.wordpress.com
    http://www.jlcomp.demon.co.uk
    To post code, statspack/AWR report, execution plans or trace files, start and end the section with the tag {noformat}{code}{noformat} (lowercase, curly brackets, no spaces) so that the text appears in {code}fixed format{code}.
    There is a +"Preview"+ tab at the top of the text entry panel. Use this to check what your message will look like before you post the message. If it looks a complete mess you're unlikely to get a response. (Click on the +"Plain text"+ tab if you want to edit the text to tidy it up.)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

  • Query about Keep Buffer Pool and Recycle Buffer Pool

    What will Keep Buffer Pool and Recycle Buffer Pool contains actually in Database Buffer Cache, specially what type of objects? I know the definitions but need to know the practical aspects about them.

    918868 wrote:
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