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From Jianwu Wang <jia...@sdsc.edu>
Subject Re: ask help for hsql conflict problem.
Date Wed, 30 Sep 2009 22:09:57 GMT
Hi Steve,

    Thanks for your info. I have to use hsql in my own java application.

    Now I worked it out by using another port for the hsql server in my 
own java application. But hsql says one hsql server should be able to 
work with multiple databases 
(http://hsqldb.org/doc/guide/ch01.html#N1013D). Not sure it doesn't work 
for me.

Best wishes

Sincerely yours

Jianwu Wang

Scientific Workflow Automation Technologies (SWAT) Laboratory
San Diego Supercomputer Center 
University of California, San Diego
San Diego, CA, U.S.A. 

Steve Loughran wrote:
>> On Tue, Sep 29, 2009 at 4:58 PM, Jianwu Wang <jianwu@sdsc.edu> wrote:
>>> Hi there,
>>>   When I have hadoop running (version 0.20.0, Pseudo-Distributed 
>>> Mode), I
>>> can not start my own java application. The exception complains that
>>> 'java.sql.SQLException: failed to connect to url
>>> "jdbc:hsqldb:hsql://localhost/hsqldb". I have to stop hadoop to 
>>> start my own
>>> java application. Both my application and hadoop use hsqldb. Does 
>>> anyone
>>> know why and can help me out of this problem?  Or tell me where to 
>>> look for
>>> hadoop hsqldb connection implementation, like which kind of hsql 
>>> server mode
>>> is used in hadoop and what is the default url of hsqldb for hadoop? 
>>> I looked
>>> into org.apache.hadoop.mapred.lib.db package but didn't find any clue.
> HSQL is a single threaded database built into the JDBC driver, >1 app 
> cannot use the same database, indeed, >1 thread cannot use it as every 
> JDBC call will block. Use a real database.

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