DB Pool Updates #103
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DB Pool Updates #103
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the new method postpones releasing the connection to the next iteration of the event loop and only releases it if the file descriptor has changed since the last `io_wait` call. This ensures we are not releasing the connection until the DB query is completed (there can be several `io_wait` calls for one query) The change is mostly caused by the bug in AR 7.0+ that makes the inital `Fiber.defer` approach unstable. We also disable the method for AR 7.2+, as it doesn't hold onto connections anymore.
AR 6.0 doesn't support passing the role to the connection handler methods
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releasing connections inside each raises "can't add a new key into hash during iteration"
`:all` option makes it explicit and removes deprecation warning on AR 7.1. AR 6.0 doesn't support this option, so we add the "polyfill"
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setting this flag allows to correctly rebuild connections in dev env with multiple DBs
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DB Pool Updates
Description
This is the prep work to have Rage's DB Pool enabled by default in v1.10.0.
Weak AR connections
The PR changes the logic behind
Fiber.deferto automatically release Active Record connections without waiting for the request to complete. Previous approach (see #66 and #80) was unstable with AR 7.0+. The new approach keeps track of the file descriptors the scheduler waits on to release the connection once the code proceeds to the next blocking call.Health checks for AR connections
With Active Record < 7.1, we enable active health checks for the DB connections that will run every second. If a connection is identified as unhealthy, the pool will reconnect the next time it is checked out. We are not going with the native Active Record approach of calling
verify!every time the connection is checked out because active health checks strike a better balance between availability and performance.The health checks are only enabled with AR < 7.1, as AR 7.1+ automatically reconnects to the database.
Other fixes
Some other fixes include the correct handling of the
idle_timeoutoption and updating the code to automatically release AR connections from all connection pools. The Fiber Scheduler is also updated to correctly handle automatic reconnects and query retries in AR 7.1+.