Hello,
I am using Connector/J [latest stable version] with MySQL 4.0.18 and InnoDB
tables.
My application occasionally performs such sequence of commands:

Connection con = pool.getConnection();
con.setAutoCommit(false);
Statement stmt = con.createStatement();
stmt.executeUpdate("update my_table set counter = counter + 1 where id = " +
id);
....
con.commit();

Is it possible that when this code snippet is performed by several threads
at once, the "counter" increment is not done correctly? Because it is what
happens to some rows of that table. Transaction isolation should be
repeatable_read, as it is default for InnoDB. Or do I have to execute
"select for update" first?

Thanks for all hints.
Filip

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hi filip,
"counter +1" code needs to be done under mutex/ sync_block in a multi
threaded app,
and has nothing to do with the database isolation type.
-dennis

On Jul 7, 2004, at 6:38 AM, Filip Rachunek wrote:


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