Re: modify cycles

Roger Binns wrote:
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> Eric S. Johansson wrote:
>> yup.  makes sense.  I wonder why someone didn't make a method 
>> implementing a transaction bounded method?  haven't tested this yet but 
>> it seems ok.  feel free to use it if it helps anyone.
> 
> Note that you need to put exception handling in your method so that
> rollback is called on errors and the isolation level restored.

what kind of exceptions?  any I can retry or are they all the hard 
failure type?  without really knowing the exceptions and the proper 
placement for begin/end/rollback, I'm guessing the form would look 
something like the following.  may need to add time delays when retrying 
and retry counts:

def transaction(connection, fcn, args**):
     success = False
     old_isolation = connection.isolation_level
     connection.isolation_level=None
     c=connection.cursor()
     c.execute("BEGIN")
     while(True):
         try:
             fcn(c,args)
             c.execute("END")
             connection.commit()
             success = True
             break
         except (..retryable exceptions...), error:
             continue
         except (..stbu exceptions...), error:
             c.execute("ROLLBACK")
             break
     connection.isolation_level = old_isolation
     return success


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