Just another more question...

Can I do writes directly in Mysql, doing replication by myself and after
reading this writes with sequoia ?

Sequoia is able to read values athough this values has not been inserted
with sequoia ?

Toni.

2009/3/25 Emmanuel Cecchet <[email protected]>

> Check the documentation in xml/sequoia.dtd, the meaning of each element is
> described.
>
> Emmanuel
>
> Toni Menendez Lopez wrote:
>
>> What is the meaning of WaitForCompletion
>>
>> 2009/3/23 Emmanuel Cecchet <[email protected] <mailto:
>> [email protected]>>
>>
>>    Hi Toni,
>>
>>    I had a quick look at the config files, I would recommend trying
>>    WaitForCompletion policy="*first*" instead of WaitForCompletion
>>    policy="*all*".
>>    You seem to have added a lot of indexes on the main recovery log
>>    table, this will significantly slowdown inserts in that table. As
>>    this table is mostly written than read, reducing the number of
>>    indexes should give you a better balance in performance.
>>    The other settings seem fine. It looks like you are loading 3
>>    other virtual databases in your controller.xml file, make sure the
>>    settings are similar.
>>    Also make sure that you don't have too much logging in
>>    log4j.properties as this can significantly slowdown the system if
>>    you turn some of them to DEBUG.
>>
>>    Hope this helps,
>>    Emmanuel
>>
>>     Sorry I think I missed the configuration files, can you have a
>>>    look just to see if you find something wrong in them, or
>>>    simething that I can improve !
>>>
>>>    2009/3/20 Toni Menendez <[email protected]
>>>    <mailto:[email protected]>>
>>>
>>>
>>>        First of all,
>>>
>>>        Thanks a lot for the help, now I write down responses ?
>>>
>>>        Emmanuel Cecchet escribió:
>>>
>>>            Toni Menendez Lopez wrote:
>>>
>>>                How many controllers are you using?
>>>                >>I am using 2 Back-Ends, which on controller in
>>>                each-backend.
>>>
>>>            I did not get that. You have 2 databases on 1 controller?
>>>
>>>        I have 4 databases in one controller, and 1 controller on
>>>        each BE.
>>>
>>>                Which version of MySQL are you using? >>server
>>>                version: 4.1.20-log
>>>                 What components are located where? >>What do you
>>>                mean with this ?
>>>
>>>            Do you have the controller(s) and the databases on
>>>            different machines?
>>>
>>>        Yes, I have 2 BackEnds on each backend same databases doing
>>>        replication.
>>>
>>>            Is your JBoss server on another machine?
>>>
>>>        No, same servers !
>>>
>>>            What is your network architecture (how are they
>>>            interconnected)?
>>>
>>>        I have a dedicated switch for this machines, so are connected
>>>        in same network witn 100Mb ethernet configuration.
>>>
>>>            Did you co-locate JBoss and Sequoia?
>>>
>>>        What do you mean with this ? You mean if they are in the same
>>>        server ? In that case : yes.
>>>
>>>                Which operating system are you using? >>Redhat
>>>                 Enterprose Linus 4 update 4  Which JVM are you using?
>>>                >>java -version
>>>                >>java version "1.5.0_10"
>>>                >>Java(TM) 2 Runtime Environment, Standard Edition
>>>                (build 1.5.0_10-b03)
>>>                >>Java HotSpot(TM) Server VM (build 1.5.0_10-b03,
>>>                mixed mode)
>>>                 What is your network configuration? >>Network
>>>                configuration, I have a private network to connect
>>>                the 2 BE between each one, and after we are using
>>>                jgroups.
>>>
>>>            If you have a single controller, you should not use group
>>>            communication and see big benefits.
>>>
>>>        I have 2 controllers one for each server !
>>>
>>>            If you have 2 controllers (one on each backend), you
>>>            should try different JGroups settings. Oftentimes, the
>>>            TCP stack gives better results. You can also give it a
>>>            try with Appia to see if performance improves.
>>>
>>>        I send you my configuration files, to see what do you think
>>>        about.
>>>
>>>        Sorry, how can I use Appia ?
>>>
>>>                What does your workload look like (reads vs writes,
>>>                transactions, ...)? >>In our case mainly writes !
>>>
>>>            Well, then you might want to reconsider the choice of
>>>            Sequoia. Sequoia will not provide you speedup for writes
>>>            (just for reads) and will certainly significantly
>>>            slowdown your write throughput. If you don't have strong
>>>            consistency constraints, you might want to consider using
>>>            asynchronous replication instead like MySQL replication.
>>>
>>>        We used sequoia mainly becouse the high availability solution
>>>        for mysql.
>>>
>>>        So, you are telling me that in case of too much writes/sec
>>>        sequoia is not a good solution ? Why ?
>>>
>>>        In our application we need both lots of reads and lots of
>>>        writes. Is there any way to write in mysql and this changes
>>>        can be read later by sequoia ?
>>>
>>>        How many writes/sec do you think we can achive in sequoia
>>>        with a very simple INSERT ?
>>>
>>>        What do you mean using asyncronous replication ?
>>>
>>>
>>>
>>>            If you are using a single controller, you might want to
>>>            set you WaitForCompletion policy to 'first' in the load
>>>            balancer settings of your virtual database configuration
>>>            file.
>>>
>>>
>>>            Hope this helps,
>>>            Emmanuel
>>>
>>>                Are you using direct JDBC or Hibernate? >>Hibernate.
>>>
>>>
>>>
>>>                   These are preliminary questions that should help
>>>                highlighting
>>>                   points worth investigating. Tuning requires some
>>>                analysis of your
>>>                   system to understand what the potential
>>>                bottlenecks can be. This
>>>                   is specific to your system and you might want to
>>>                look for someone
>>>                   providing consulting services in your area for an
>>>                appropriate
>>>                   answer to your needs
>>>
>>>                 >> First of all I would like to try to do the
>>>                tinning by ourselves before contacting any external
>>>                consulting.  I would like to know if there is any
>>>                parameter to tune the sequoia.
>>>
>>>                   Thanks for your interest in Sequoia,
>>>                   Emmanuel
>>>
>>>                   --     Emmanuel Cecchet
>>>                   FTO @ Frog Thinker Open Source Development &
>>>                Consulting
>>>                   --
>>>                   Web: http://www.frogthinker.org
>>>                <http://www.frogthinker.org/>
>>>                <http://www.frogthinker.org/>
>>>                   email: [email protected]
>>>                <mailto:[email protected]>
>>>                <mailto:[email protected]
>>>                <mailto:[email protected]>>
>>>                   Skype: emmanuel_cecchet
>>>
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>>>                   <mailto:[email protected]
>>>                <mailto:[email protected]>>
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>>>
>>>
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>>>
>>>        Thanks,
>>>
>>>        Toni.
>>>
>>>
>>>
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>>
>>
>>    -- Emmanuel Cecchet FTO @ Frog Thinker Open Source Development &
>>    Consulting -- Web: http://www.frogthinker.org
>>    <http://www.frogthinker.org/>
>>
>>    email: [email protected] <mailto:[email protected]>
>>    Skype: emmanuel_cecchet
>>
>>
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>
>
> --
> Emmanuel Cecchet
> FTO @ Frog Thinker Open Source Development & Consulting
> --
> Web: http://www.frogthinker.org
> email: [email protected]
> Skype: emmanuel_cecchet
>
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