Default transaction isolation level in jConnect 7.0

[Dan H]

Versions:
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jConnect (TM) for JDBC(TM)/7.00(Build 26548)/P/EBF19559/JDK16/Thu Sep 29 9:30:50 2011

The issue:
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Deadlocks occur in jBoss jBPM related tables. Problem disappears when we explicitly set isolation level to TRANSACTION_READ_COMMITTED in the server's Sybase datasource config. Similar issue reported by WebSphere users.

Observations:
===============
This seems to be due to the fact that jConnect 7 uses higher isolation level - "2" instead of "1" - according to jConnect engineer. According to the same expert we could downgrade, like:

UPDATE dbo.spt_mda
SET query='1'
WHERE mdinfo = 'TRANSACTIONLEVELDEFAULT'
AND querytype = 5
AND query = '2'

UPDATE dbo.spt_mda
SET query='select 1'
WHERE mdinfo = 'TRANSACTIONLEVELDEFAULT'
AND querytype = 2
AND query = 'select 2'

Questions:
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jConnect upgrade script has comments like "note - transaction levels here match Connection.TRANSACTION" - does this mean java.sql.Connection (see for example http://docs.oracle.com/javase/6/docs/api/constant-values.html#java.sql.Connection.TRANSACTION_NONE ):
public static final int TRANSACTION_NONE 0
public static final int TRANSACTION_READ_COMMITTED 2
public static final int TRANSACTION_READ_UNCOMMITTED 1
public static final int TRANSACTION_REPEATABLE_READ 4
public static final int TRANSACTION_SERIALIZABLE 8

If so, it almost looks like we'd be changing from 2=TRANSACTION_READ_COMMITTED to 1= TRANSACTION_READ_UNCOMMITTED ?

Did anyone have to either explicitly change isolation level or modify spt_mda?

Thanks
Dan