Record the last time a connection was used on the connection object
Ref T11458. Currently, we're very aggressive about closing connections.
I want to change things so we only close connections we haven't used recently (for example: no activity in the last 15 seconds). This should let us do a better job of holding open approximately only the connections we actually need in a wider range of cases.
Ran some code that uses queries.
This doesn't do anything on its own; see next diff in Phabricator for meaningful changes.
Reviewed By: chad
Maniphest Tasks: T11458
Differential Revision: https://secure.phabricator.com/D16388