Introduce the ability to kill competing transactions that hold exclusive lock during swap #23
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shayonj
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Feb 6, 2022
| def lock_exclusive(client, table) | ||
| attempts ||= 1 | ||
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| client.connection.async_exec("SET lock_timeout = '#{client.wait_time_for_lock}s'; BEGIN;") |
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it sets a lock_timeout which matches client.wait_time_for_lock. we use this ability for retries since on failure to acquire the lock PG::LockNotAvailable/PG::InFailedSqlTransaction is raised
shayonj
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…ive lock during swap This introduces wait_time_for_lock and kill_backends as new flags. By default pgosc won't kill any backends if it cannot acquire an exclusive lock to perform the swap. It will retry upto 3 times and for the duration specified in wait_time_for_lock (default: 10s). So, in total 30s. Configurable. If kill_backends/kill-backend is set to true (supplied), then it will kill the backend on each try it couldn't acquire the lock, upto 3 times before exiting. Though, after killing the backends after 1st attempt should work. Specs added. A bit messy for now. Refactor in the end
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This introduces
wait_time_for_lockandkill_backendsas new flags.By default
pgoscwon't kill any backends if it cannot acquire anAccessExclusiveLockto perform the swap. It will retry upto 3 timesand for the duration specified in
wait_time_for_lock(default:10s).So, in total 30s. Configurable. If
kill_backends/kill-backendis set to true (supplied), then it will kill the backend on each try
it couldn't acquire the lock, upto 3 times before exiting. Though,
after killing the backends after 1st attempt should work.
Specs added. A bit messy for now. Refactor in the end
closes #16