I've checked netstat and there are only 15 mysql connections (status is still reporting the same): Pool size: 20 Connections in pool: 19 Current Overflow: -36 Current Checked out connections: -35
On our other servers, the number of connections (from netstat) matches up with the pool status as expected. I will try and recreate the problem with a test. Many thanks! On Monday, June 27, 2016 at 4:36:21 PM UTC+1, Mike Bayer wrote: > > Well it is possible QueuePool doesn't do the right thing under eventlet, > though we use it a lot w/ eventlet in Openstack and I've tested it > myself quite a bit. Have not peeked at this number, however. > > You'd need to produce for me a self contained test suite that > illustrates this behavior occurring, that would be very helpful in order > to track this down. > > Do you see too many actual database connections in play when this > condition occurs ? That is, using netstat you'd see more than 120 > connections. > > > > On 06/27/2016 11:30 AM, 'Dave Puffin' via sqlalchemy wrote: > > Thanks for the reply :) > > > > I think you're right in that it must be threading related somehow, but > > it looks like all the monkeypatching has been applied correctly. If I > > examine the locking object used in the pool I get: > > > >>>> type(engine.pool._overflow_lock) > > > > <class 'eventlet.semaphore.Semaphore'> > > > > > > On Mon, Jun 27, 2016 at 4:21 PM, Mike Bayer <mik...@zzzcomputing.com > <javascript:> > > <mailto:mik...@zzzcomputing.com <javascript:>>> wrote: > > > > > > > > On 06/27/2016 10:48 AM, davepuffin via sqlalchemy wrote: > > > > Hi > > > > QueuePool.status() is returning some odd looking negative values > > from > > one of our production applications. > > > > engine.pool.status() > > > > 'Pool size: 20 Connections in pool: 19 Current Overflow: -36 > Current > > Checked out connections: -35' > > > > The pool was initialised with: pool_size=20, max_overflow=100. > > > > > > Does anyone know of any scenarios that could cause this? > > > > > > We are using SQLAlchemy==1.0.13 connecting to MySql 5.6. > > The application runs in a single python process that uses > > eventlet to > > manage many greenthreads. > > > > > > > > well that's very likely to be related, are you monkeypatching all > > thread / Lock primitives before importing SQLAlchemy? QueuePool > > relies upon traditional thread and locking primitives which will > > fail if you use them unpatched in a green-thread situation. The > > Queue here is basically Python's Queue.Queue so it appears like the > > queue has been populated with more objects than it is supposed to > allow. > > > > > > > > The situation appears to occur sometime after the overflow has > > been used. > > > > Thanks > > > > -- > > You received this message because you are subscribed to the > Google > > Groups "sqlalchemy" group. > > To unsubscribe from this group and stop receiving emails from > > it, send > > an email to sqlalchemy+...@googlegroups.com <javascript:> > > <mailto:sqlalchemy%2bunsubscr...@googlegroups.com <javascript:>> > > > <mailto:sqlalchemy+unsubscr...@googlegroups.com <javascript:> > > <mailto:sqlalchemy%2bunsubscr...@googlegroups.com <javascript:>>>. > > > To post to this group, send email to sqlal...@googlegroups.com > <javascript:> > > <mailto:sqlal...@googlegroups.com <javascript:>> > > <mailto:sqlal...@googlegroups.com <javascript:> > > <mailto:sqlal...@googlegroups.com <javascript:>>>. > > Visit this group at https://groups.google.com/group/sqlalchemy. > > For more options, visit https://groups.google.com/d/optout. > > > > > > -- > > You received this message because you are subscribed to a topic in > > the Google Groups "sqlalchemy" group. > > To unsubscribe from this topic, visit > > https://groups.google.com/d/topic/sqlalchemy/UWxi-bknpZE/unsubscribe. > > > To unsubscribe from this group and all its topics, send an email to > > sqlalchemy+...@googlegroups.com <javascript:> > > <mailto:sqlalchemy%2bunsubscr...@googlegroups.com <javascript:>>. > > To post to this group, send email to sqlal...@googlegroups.com > <javascript:> > > <mailto:sqlal...@googlegroups.com <javascript:>>. > > Visit this group at https://groups.google.com/group/sqlalchemy. > > For more options, visit https://groups.google.com/d/optout. > > > > > > -- > > You received this message because you are subscribed to the Google > > Groups "sqlalchemy" group. > > To unsubscribe from this group and stop receiving emails from it, send > > an email to sqlalchemy+...@googlegroups.com <javascript:> > > <mailto:sqlalchemy+unsubscr...@googlegroups.com <javascript:>>. > > To post to this group, send email to sqlal...@googlegroups.com > <javascript:> > > <mailto:sqlal...@googlegroups.com <javascript:>>. > > Visit this group at https://groups.google.com/group/sqlalchemy. > > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. 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