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From Ejaz X Mohammed <ejaz.moham...@jpmorgan.com>
Subject RE: Locks
Date Wed, 14 Apr 2010 16:43:07 GMT
I changed the code to use plain jdbc instead of ibatis ... as I said I'm doing just SELECT
... I started no tranasaction .. now I don't see any locks, perf seems to be better too ...

If we start a transaction, sybase takes locks ... read lock for SELECT ... 

Can we avoid starting TX during select in ibatis?

Ejaz


-----Original Message-----
From: Jeff Butler [mailto:jeffgbutler@gmail.com] 
Sent: Wednesday, April 14, 2010 11:36 AM
To: user-java@ibatis.apache.org
Subject: Re: Locks

I assume you're using SIMPLE datasource.  With that data source, the
isolation level is set as a driver default.  I just did a quick test
with HSQLDB and the default seems to be TRANSACTION_READ_COMMITTED - a
middle of the road isolation level.  Maybe there is some setting on
the Sybase driver that will allow you to change the default isolation
level?

Alternatively, you can do it in code like this:

try {
  sqlMapClient.startTransaction(Connection.TRANSACTION_READ_UNCOMMITTED);

  -- do some work
} finally {
  sqlMapClient.endTransaction();
}

If you are using some other datasource (like JNDI), then you'll need
to look to that datasource for information about changing the
isolation level.

Jeff Butler





On Wed, Apr 14, 2010 at 9:51 AM, Ejaz X Mohammed
<ejaz.mohammed@jpmorgan.com> wrote:
> These are my settings ...
>
>    <!--
>    These settings control SqlMap configuration details, primarily to do with transaction
>    management. They are all optional (see the Developer Guide for more).
>    -->
>    <settings
>            cacheModelsEnabled="true"
>            enhancementEnabled="true"
>            lazyLoadingEnabled="true"
>            maxRequests="32"
>            maxSessions="10"
>            maxTransactions="5"
>            useStatementNamespaces="true"
>        />
>
>    <!--
>    Configure a datasource to use with this SQL Map using SimpleDataSource.
>    Notice the use of the properties from the above resource
>    -->
>    <transactionManager type="JDBC" >
>        <dataSource type="....">
>            <property name="JDBC.Driver" value="${jdbc.driver}"/>
>            <property name="JDBC.ConnectionURL" value="${jdbc.url}"/>
>            <property name="JDBC.Username" value="${jdbc.user}"/>
>            <property name="JDBC.Password" value="${jdbc.password}"/>
>            <property name="JDBC.DefaultAutoCommit" value="true"/>
>        </dataSource>
>    </transactionManager>
>
>
>
>
> -----Original Message-----
> From: Jeff Butler [mailto:jeffgbutler@gmail.com]
> Sent: Wednesday, April 14, 2010 9:44 AM
> To: user-java@ibatis.apache.org
> Subject: Re: Locks
>
> It's dependent on the transaction isolation level set on your
> connection.  There are many variables involved - what is your
> environment (POOLED, UNPOOLED, JNDI, etc.)?
>
> Jeff Butler
>
>
> On Wed, Apr 14, 2010 at 9:38 AM, Ejaz X Mohammed
> <ejaz.mohammed@jpmorgan.com> wrote:
>> Hello,
>>
>>
>>
>> I have an application running on Sybase. DBAs tell me that it is generating
>> too many locks ... I know that all I'm doing is SELECT.
>>
>>
>>
>> I'm not sure how SELECT can create locks in database.
>>
>>
>>
>> Any suggestions ?
>>
>>
>>
>> Thanks
>>
>> Ejaz
>>
>> This email is confidential and subject to important disclaimers and
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