db-derby-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Mike Matrigali <mikem_...@sbcglobal.net>
Subject Re: Derby 10.1.1 - Question about transactions
Date Tue, 30 Aug 2005 16:45:46 GMT
There is a typo in the info below, the default isolation level for
derby is read committed.

Mike Matrigali wrote:
> what you need to read up about is isolation level and transactions.
> Derby implements
> jdbc standard isolation levels: read uncommitted, read committed,
> repeatable read, serializable.
> 
> For all isolation levels derby will hold the write lock on the rows
> inserted until end of transaction.  For all isolation levels except
> for read uncommitted, reading transactions will block before reading
> uncommitted inserted rows by the writer.  The default isolation level
> is read uncommitted.
> 
> From your brief description I don't think you have to do anything,
> other than insure that the write transactions are the scope that
> you need.  Note that by default autocommit is enabled so every
> statement issues a commit - which does not sound like what you
> want.
> 
> /mikem
> 
> Kostas Karadamoglou wrote:
> 
>> Hello all,
>>
>> I am developing an application wich uses Derby 10.1.1
>>
>> The application has multiple clients/ read connections that read
>> tables and one  write conenction that write into the tables.
>>
>>
>> The connection that modifies the table mostly inserts rows.
>>
>> There is a potential problem of a user/read connection reading data
>> while the write connection inserts rows. This can cause read
>> connection to execute outdated sql statements.
>>
>> How can I stop read connections to read data before the write
>> connection commit the insertions.
>>
>> I know that there is a LOCK TABLE statement with Derby but I want to
>> avoid it (I don't want to add string manipulation of statements).
>>
>> Can I use the setIsolationLevel of JDBC Connection?
>>
>> Which level is most appropriate?
>>
>> The method is defined at the Connection class. Does affect all the
>> connections or only the one that called the method?
>>
>>
>>
> 
> 

Mime
View raw message