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Posted to ojb-user@db.apache.org by Phil Warrick <ph...@mcgill.ca> on 2003/10/02 05:04:47 UTC
ODMG patch: per-transaction implicit locking
Hi,
I have been using the following patch to control the implicit locking
flag at the transaction level (instead of a single global setting). I
developed it because I wanted to do ODMG reading without implicit
locking and to do ODMG writing with implicit locking. Even with a
schema that is fully proxied, I found that read locking propagates
across the proxies leading to a potentially large graph traversal.
The changes are really just the addition of a
setImplicitLocking(boolean) method to the following three classes:
1)org.apache.ojb.odmg.TransactionImpl
2)org.apache.ojb.odmg.OJB
3)org.apache.ojb.odmg.OJBJ2EE_2
This has been tested in both a single JVM setting and in a J2EE/EJB
environment.
The changes (below) are so trivial that I didn't do make a true patch
file. I hope one of the developers can review these changes and
incorporate them if appropriate.
This change can be thought of as an extension to the ODMG api, giving
greater control to the locking stategy (the ODMG standard enforces no
particular implicit locking strategy). The global setting
"ImplicitLocking" specified in OJB.properties is used when a
org.apache.ojb.odmg.TransactionImpl is created. A subsequent call to
OJB#setImplicitLocking(boolean) or
OJBJ2EE_2#setImplicitLocking(boolean) within the transaction overrides
the global setting.
The reason that I did not use the approach
((OjbConfiguration)getConfiguration()).setUseImplicitLocking(in);
to set the global configuration setting is that this is not thread-safe,
as far as I can tell.
Of course if there's an easier way to do this I'd like to know.
Phil
1) org.apache.ojb.odmg.TransactionImpl.java
public void setImplicitLocking(boolean in)
{
useImplicitLocking = in;
}
2) org.apache.ojb.odmg.OJB.java
public void setImplicitLocking(boolean in)
{
((TransactionImpl)currentTransaction()).setImplicitLocking(in);
}
3) org.apache.ojb.odmg.OJBJ2EE_2.java
public void setImplicitLocking(boolean in)
{
currentTransaction();
((TransactionImpl)super.currentTransaction()).setImplicitLocking(in);
}
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Re: ODMG patch: per-transaction implicit locking
Posted by Phil Warrick <ph...@mcgill.ca>.
Hi Thomas,
Great. I'll try it with the next release.
Phil
Thomas Mahler wrote:
> Hi Phil,
>
> I like your idea. I've just checked in some code that implements it. I
> added the method setImplicitLocking to the TransactionExt interface.
> This allows to have it available in TransactionImpl *and* in
> NarrowTransaction.
> By this trick I only had to change OJB but not OJBJ2EE_2.
>
> thanks for this interesting patch!
>
> Thomas
>
> Phil Warrick wrote:
>
>> Hi,
>>
>> I have been using the following patch to control the implicit locking
>> flag at the transaction level (instead of a single global setting). I
>> developed it because I wanted to do ODMG reading without implicit
>> locking and to do ODMG writing with implicit locking. Even with a
>> schema that is fully proxied, I found that read locking propagates
>> across the proxies leading to a potentially large graph traversal.
>>
>> The changes are really just the addition of a
>> setImplicitLocking(boolean) method to the following three classes:
>>
>> 1)org.apache.ojb.odmg.TransactionImpl
>> 2)org.apache.ojb.odmg.OJB
>> 3)org.apache.ojb.odmg.OJBJ2EE_2
>>
>> This has been tested in both a single JVM setting and in a J2EE/EJB
>> environment.
>>
>> The changes (below) are so trivial that I didn't do make a true patch
>> file. I hope one of the developers can review these changes and
>> incorporate them if appropriate.
>>
>> This change can be thought of as an extension to the ODMG api, giving
>> greater control to the locking stategy (the ODMG standard enforces no
>> particular implicit locking strategy). The global setting
>> "ImplicitLocking" specified in OJB.properties is used when a
>> org.apache.ojb.odmg.TransactionImpl is created. A subsequent call to
>> OJB#setImplicitLocking(boolean) or
>> OJBJ2EE_2#setImplicitLocking(boolean) within the transaction overrides
>> the global setting.
>>
>> The reason that I did not use the approach
>> ((OjbConfiguration)getConfiguration()).setUseImplicitLocking(in);
>>
>> to set the global configuration setting is that this is not
>> thread-safe, as far as I can tell.
>>
>> Of course if there's an easier way to do this I'd like to know.
>>
>> Phil
>>
>> 1) org.apache.ojb.odmg.TransactionImpl.java
>> public void setImplicitLocking(boolean in)
>> {
>> useImplicitLocking = in;
>> }
>>
>> 2) org.apache.ojb.odmg.OJB.java
>> public void setImplicitLocking(boolean in)
>> {
>> ((TransactionImpl)currentTransaction()).setImplicitLocking(in);
>> }
>>
>> 3) org.apache.ojb.odmg.OJBJ2EE_2.java
>> public void setImplicitLocking(boolean in)
>> {
>> currentTransaction();
>> ((TransactionImpl)super.currentTransaction()).setImplicitLocking(in);
>> }
>>
>>
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>> To unsubscribe, e-mail: ojb-user-unsubscribe@db.apache.org
>> For additional commands, e-mail: ojb-user-help@db.apache.org
>>
>>
>
>
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>
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Re: ODMG patch: per-transaction implicit locking
Posted by Thomas Mahler <th...@web.de>.
Hi Phil,
I like your idea. I've just checked in some code that implements it. I
added the method setImplicitLocking to the TransactionExt interface.
This allows to have it available in TransactionImpl *and* in
NarrowTransaction.
By this trick I only had to change OJB but not OJBJ2EE_2.
thanks for this interesting patch!
Thomas
Phil Warrick wrote:
> Hi,
>
> I have been using the following patch to control the implicit locking
> flag at the transaction level (instead of a single global setting). I
> developed it because I wanted to do ODMG reading without implicit
> locking and to do ODMG writing with implicit locking. Even with a
> schema that is fully proxied, I found that read locking propagates
> across the proxies leading to a potentially large graph traversal.
>
> The changes are really just the addition of a
> setImplicitLocking(boolean) method to the following three classes:
>
> 1)org.apache.ojb.odmg.TransactionImpl
> 2)org.apache.ojb.odmg.OJB
> 3)org.apache.ojb.odmg.OJBJ2EE_2
>
> This has been tested in both a single JVM setting and in a J2EE/EJB
> environment.
>
> The changes (below) are so trivial that I didn't do make a true patch
> file. I hope one of the developers can review these changes and
> incorporate them if appropriate.
>
> This change can be thought of as an extension to the ODMG api, giving
> greater control to the locking stategy (the ODMG standard enforces no
> particular implicit locking strategy). The global setting
> "ImplicitLocking" specified in OJB.properties is used when a
> org.apache.ojb.odmg.TransactionImpl is created. A subsequent call to
> OJB#setImplicitLocking(boolean) or
> OJBJ2EE_2#setImplicitLocking(boolean) within the transaction overrides
> the global setting.
>
> The reason that I did not use the approach
> ((OjbConfiguration)getConfiguration()).setUseImplicitLocking(in);
>
> to set the global configuration setting is that this is not thread-safe,
> as far as I can tell.
>
> Of course if there's an easier way to do this I'd like to know.
>
> Phil
>
> 1) org.apache.ojb.odmg.TransactionImpl.java
> public void setImplicitLocking(boolean in)
> {
> useImplicitLocking = in;
> }
>
> 2) org.apache.ojb.odmg.OJB.java
> public void setImplicitLocking(boolean in)
> {
> ((TransactionImpl)currentTransaction()).setImplicitLocking(in);
> }
>
> 3) org.apache.ojb.odmg.OJBJ2EE_2.java
> public void setImplicitLocking(boolean in)
> {
> currentTransaction();
> ((TransactionImpl)super.currentTransaction()).setImplicitLocking(in);
> }
>
>
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> To unsubscribe, e-mail: ojb-user-unsubscribe@db.apache.org
> For additional commands, e-mail: ojb-user-help@db.apache.org
>
>
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