Re: [openstack-dev] [all][oslo.db] Repeatable Read considered harmful

2015-03-31 Thread Eugene Nikanorov
Hi Matthew, I'll add just 2c: We've tried to move from repeatable-read to read committed in Neutron project. This change actually has caused multiple deadlocks during regular tempest test run. That is a known problem (the issue with eventlet and currect mysql client library), but anyway, at

Re: [openstack-dev] [all][oslo.db] Repeatable Read considered harmful

2015-03-31 Thread Mike Bayer
Eugene Nikanorov enikano...@mirantis.com wrote: Hi Matthew, I'll add just 2c: We've tried to move from repeatable-read to read committed in Neutron project. This change actually has caused multiple deadlocks during regular tempest test run. That is a known problem (the issue with

Re: [openstack-dev] [all][oslo.db] Repeatable Read considered harmful

2015-03-31 Thread Salvatore Orlando
On 31 March 2015 at 17:22, Mike Bayer mba...@redhat.com wrote: Eugene Nikanorov enikano...@mirantis.com wrote: Hi Matthew, I'll add just 2c: We've tried to move from repeatable-read to read committed in Neutron project. This change actually has caused multiple deadlocks during

[openstack-dev] [all][oslo.db] Repeatable Read considered harmful

2015-02-06 Thread Matthew Booth
I was surprised recently to discover that MySQL uses repeatable read for transactions by default. Postgres uses read committed by default, and SQLite uses serializable. We don't set the isolation level explicitly anywhere, so our applications are running under different isolation levels depending