Fix dead locks in connection pool #499
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and pool Locking connection and pool at the same time can lead to deadlock. Consider that connection.close also locks connection.
pool Locking connection and pool can lead to deadlock. Consider that connection.close locks connection.
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Eh, I don't understand this code well enough to say with confidence that those changes are correct. At first glance they look correct, left just one comment about improving commit message.
I wish it was written in a more dev-friendly way: one thread/task/whatever than handles connection / pool, receives events etc. Then there is basically no need for any locks, since things only have one owner.
and pool Locking connection a pool can lead to a deadlock. Consider that connection.close also locks connection. This commit also fixes condition for closing connection right away. Instead of checking there is no in-flight requests it now checks if in-flight requests less or equal than orphaned requests, since orphaned requests still counts as in-flight and can be safely disregarded when connection is dropped.
and connection Locking connection and pool at the same time lead to dead lock. Consider connection.close locks connection.
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We could have rewritten it, but I think it would be way better to invest into the wrapper around rust-driver. |
Investigating problems with scaling test for #473 I have found dead locks in both pools implementations:
HostConnectionandHostConnectionPoolAll these deadlocks caused by following reasons:
Solution to all of them is to avoid locking pool and session at the same time.
Tests were not added because for most cases there could be no reliable test possible.
Pre-review checklist
I added relevant tests for new features and bug fixes.I have provided docstrings for the public items that I want to introduce.I have adjusted the documentation in./docs/source/.I added appropriateFixes:annotations to PR description.