On Nov 27, 2014 4:39 PM, "Chris Angelico" wrote:
>
> On Fri, Nov 28, 2014 at 5:02 AM, Ian Kelly wrote:
> > On Nov 27, 2014 4:26 AM, "Frank Millman" wrote:
> >> All Python database adaptors that I have used start a transaction when
you
> >> open a cursor. I have just re-read DB-API 2.0, and I can
On Fri, Nov 28, 2014 at 5:57 PM, Frank Millman wrote:
> cur.execute('commit') tells the database to commit the transaction, but the
> adaptor is not aware of this, so does not reset. Therefore the next command
> does not trigger starting a new transaction.
>
> I have now learned another lesson - n
"Frank Millman" wrote in message
news:m5924d$nbq$1...@ger.gmane.org...
>
>
> This seems to confirm what I thought, but then I continued, and was
> surprised at the result.
>
> I can repeat these lines at will -
>
> cur.execute('SELECT * FROM mytable') - 4
> conn.commit() - 3
>
> But if I do thi
On Fri, Nov 28, 2014 at 4:44 PM, Frank Millman wrote:
> There seems to be a difference between conn.commit() and
> cur.execute('commit'), which leaves the connection in a different state.
Yes, if a connection library offers a way to commit/roll back, it's
usually best to use that.
> However, for
"Dennis Lee Bieber" wrote in message
news:4loe7at2ls7tfq0oe041ru9svvsm8ak...@4ax.com...
> On Thu, 27 Nov 2014 12:24:39 +0200, "Frank Millman"
> declaimed the following:
>
>
>>All Python database adaptors that I have used start a transaction when you
>>open a cursor. I have just re-read DB-API 2
On Fri, Nov 28, 2014 at 5:02 AM, Ian Kelly wrote:
> On Nov 27, 2014 4:26 AM, "Frank Millman" wrote:
>> All Python database adaptors that I have used start a transaction when you
>> open a cursor. I have just re-read DB-API 2.0, and I cannot see anything
>> that specifies this behaviour, but AFAIC
On Nov 27, 2014 4:26 AM, "Frank Millman" wrote:
> All Python database adaptors that I have used start a transaction when you
> open a cursor. I have just re-read DB-API 2.0, and I cannot see anything
> that specifies this behaviour, but AFAICT this is what happens.
I don't know how others work, b
On Thu, Nov 27, 2014 at 9:24 PM, Frank Millman wrote:
> "PostgreSQL by default commits between each statement unless you explicitly
> start a transaction."
>
> All Python database adaptors that I have used start a transaction when you
> open a cursor. I have just re-read DB-API 2.0, and I cannot s
Hi all
I just learned something about database transactions, locking, and DB-API
2.0.
I wondered why a PostgreSQL statement was hanging. On investigation, it was
waiting to acquire a lock. On further investigation, the lock was held by a
simple SELECT statement. This surprised me.
I got a clu
