Re: [MonetDB-users] Commit failure on concurrent transactions

Fabian, thanks very much for your answer. So, is MonetDB SQL using optimistic transaction control? Thanks very much! Best regards, Anderson Supriano

From: Fabian Groffen To: Anderson Supriano CC: monetdb-users@lists.sourceforge.net Subject: Re: [MonetDB-users] Commit failure on concurrent transactions Date: Wed, 8 Mar 2006 09:05:13 +0100

Hi Anderson,

Thanks for your interest in MonetDB/SQL. The short answer to your question is: no you can't. The longer answer: MonetDB/SQL doesn't do locking, instead, it does a fully serialisable transaction. You will get a warning if you try to change this serialisability, because only full is supported. That also explains that you get these exceptions on commit; some other transaction finished earlier. If you want to get rid of this, you can try to use only one Connection, but that obviously doesn't allow you to have multiple concurrent transactions.

I hope this helps and regards

On 07-03-2006 20:52:34 -0300, Anderson Supriano wrote:

...

Hi!

I am running several concurrent transactions on Monet DB using JDBC and I'm getting an error when commiting a transaction:

java.sql.SQLException: COMMIT: failed ERROR: COMMIT: transaction is aborted because of concurency conflicts, will ROLLBACK instead at

nl.cwi.monetdb.jdbc.MonetConnection$ResponseList.executeQuery(MonetConnection.java:2185)

...

at

nl.cwi.monetdb.jdbc.MonetConnection$ResponseList.processQuery(MonetConnection.java:1937)

...

at nl.cwi.monetdb.jdbc.MonetConnection.commit(MonetConnection.java:443)

Is there a way that this exception can be handled in order to have all transactions working (even if waiting the last one to be finished)?

I am using MonetDB-4.10.0 and SQL-2.10.0.

Thanks for your cooperation.

Best regards, Anderson Supriano

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