Very weird behavior in MySQLdb "execute"

[John Nagle]

Carsten Haese wrote:
> On Mon, 2008-02-04 at 11:30 -0800, John Nagle wrote:
>> Restarting the MySQL instance changes the database.  The entry "google.com"
>> disappears, and is replaced by "www.google.com".  This must indicate a hanging
>> transaction that wasn't committed.
>>
>> But that transaction didn't come from the Python IDLE session I've been
>> making test calls from.  Those queries should match the graphical client
>> exactly.
>>
>> So why don't they agree?
> 
> I don't have a definitive answer, but I do have a piece of generic
> advice. If two database sessions receive differing results, the cause
> could be any of the following factors:
> 
> 1) One session is in a transaction, but the other is not.
> 
> 2) Both sessions are in a transaction, but they are at different
> isolation levels.
> 
> 3) Both sessions are in a transaction, but the transactions were started
> at different times.

     I see what's wrong, I think.  I haven't been doing a commit after
a SELECT.  I've been careful to commit after write-type actions,
but not after read-only actions.  I'm using InnoDB in default mode,
which is REPEATABLE READ, and I've recently switched to long-running
processes which keep the database connection open for hours.  So the
data view for a given connection never changes, regardless of what's
happening in other threads.

				John Nagle