Re: [GCSQL] DatabaseError: 0: Connection is already in use

Thanks for the good pointer. I'll reduce the lock timeout and see if
that helps.

Cheers,
Jake

On Mon, Jun 25, 2012 at 7:55 PM, Ken Ashcraft <kash@google.com> wrote:
> On Mon, Jun 25, 2012 at 4:38 PM, Jake Czyz <jjc.work@gmail.com> wrote:
>>
>> Yes, that makes sense.  It pops up in a finally clause of a
>> try/except/finally block, which was meant to ensure tables are
>> unlocked in the event of other DB snafus.  I guess if the snafu is a
>> deadline exception,  I never see it because the finally gets executed
>> (and this error pops up) before the Deadline Exceeded is re-raised.
>>
>> Thanks.  This still sucks, but at least I have a better understanding
>> of why.  Darn deadlines... :-)
>>
>
> I agree that it could be better.  If the query goes past its deadline, the
> Cloud SQL server will close the connection (and therefore release the locks)
> with the assumption that the application is long gone.  But that doesn't
> happen until the query completes.  Since mysql doesn't support deadlines, it
> would be better to snipe the query as soon as the host server detects that
> the query is past its deadline.  No promises there since that might be
> tricky to implement.
>
> Here is a SO question that might be helpful for you in the meantime:
> http://stackoverflow.com/questions/2137084/setup-mysql-query-timeout
>
>
> Ken
>
>>
>>
>> On Mon, Jun 25, 2012 at 7:32 PM, Ken Ashcraft <kash@google.com> wrote:
>> > This error typically happens when you have a deadline exceeded
>> > exception.
>> >  The app gives up, but the query is still running on the server.  If you
>> > try
>> > to do anything else with the connection, the server will complain that
>> > the
>> > connection is already in use.  So if you get the "connection already in
>> > use"
>> > error, it means that you probably have some place else in your code
>> > where
>> > you ignored the deadline exceeded exception and reused a connection.
>> >
>> > On Sat, Jun 23, 2012 at 5:47 AM, Jake Czyz <jjc.work@gmail.com> wrote:
>> >>
>> >> Hi Ken,
>> >>
>> >> Thanks, but could you please clarify?  Do you mean I need to catch
>> >> this error, recreate a connection and retry the same query?
>> >>
>> >> Jake
>> >>
>> >>
>> >>
>> >> On Fri, Jun 22, 2012 at 4:15 PM, Ken Ashcraft <kash@google.com> wrote:
>> >> > It means that the query is still executing on the server.  You need
>> >> > to
>> >> > throw
>> >> > away the connection and create a new one.
>> >> >
>> >> >
>> >> > On Fri, Jun 22, 2012 at 1:48 AM, Jake Czyz <jjc.work@gmail.com>
>> >> > wrote:
>> >> >>
>> >> >> Hello,
>> >> >>
>> >> >> My GAE app gets the following error occasionally during GC-SQL
>> >> >> calls,
>> >> >> when unlocking previously locked tables.  Searching for the error
>> >> >> turned up nothing.  Does anyone have an idea about what could cause
>> >> >> it?
>> >> >>
>> >> >> <snip>
>> >> >>    cursor.execute('UNLOCK TABLES') #always unlock
>> >> >>  File "/base/python27_runtime/
>> >> >> python27_lib/versions/1/google/storage/speckle/python/api/rdbms.py",
>> >> >> line 424, in execute
>> >> >>    self._DoExec(request)
>> >> >>  File
>> >> >>
>> >> >>
>> >> >> "/base/python27_runtime/python27_lib/versions/1/google/storage/speckle/python/api/rdbms.py",
>> >> >> line 355, in _DoExec
>> >> >>    response = self._conn.MakeRequest('Exec', request)
>> >> >>  File
>> >> >>
>> >> >>
>> >> >> "/base/python27_runtime/python27_lib/versions/1/google/storage/speckle/python/api/rdbms.py",
>> >> >> line 711, in MakeRequest
>> >> >>    response = self._MakeRetriableRequest(stub_method, request)
>> >> >>  File
>> >> >>
>> >> >>
>> >> >> "/base/python27_runtime/python27_lib/versions/1/google/storage/speckle/python/api/rdbms.py",
>> >> >> line 742, in _MakeRetriableRequest
>> >> >>    sql_exception.message))
>> >> >> DatabaseError: 0: Connection is already in use.
>> >> >>
>> >> >>
>> >> >> Thanks in advance,
>> >> >> Jake
>> >> >
>> >> >
>> >
>> >
>
>