rabbit_db: Eliminate the delete_queue Khepri transaction (backport #14902)#15954
Merged
rabbit_db: Eliminate the delete_queue Khepri transaction (backport #14902)#15954
delete_queue Khepri transaction (backport #14902)#15954Conversation
(cherry picked from commit 6eeb339)
... by using `keep_while` conditions on bindings and auto-delete exchanges. [Why] The `delete_queue` transaction's anonymous function has to be extracted by Horus, like any Khepri transaction. This is an expensive operation, but Horus uses caching to avoid most work after the first extraction. Unfortunately, even with this caching, this transaction is still very expensive when there are massive simultaneous deletions of queues. For instance when the queues' lifetime is linked to that of many clients, and all these clients get disconnected at once. [How] This patch removes the transaction entirely. Instead, it uses `keep_while` conditions on bindings and auto-delete exchanges to let Khepri handle the deletion of semantically related tree nodes. RabbitMQ just has to make a simle "delete this queue" command. To maintain backward compatibility, we introduce the `tie_binding_to_dest_with_keep_while_cond` feature flag. Its `enable` callback will take care of rewriting all bindings and auto-delete exchanges record in the store to add the new `keep_while` conditions. The binding deletion transaction is also simplified because it benefits from the `keep_while` conditions. We may be able to replace this transaction is the future as well in the same manner. (cherry picked from commit de43879)
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… by using
keep_whileconditions on bindings and auto-delete exchanges.Why
The
delete_queuetransaction's anonymous function has to be extracted by Horus, like any Khepri transaction. This is an expensive operation, but Horus uses caching to avoid most work after the first extraction.Unfortunately, even with this caching, this transaction is still very expensive when there are massive simultaneous deletions of queues. For instance when the queues' lifetime is linked to that of many clients, and all these clients get disconnected at once.
How
This patch removes the transaction entirely. Instead, it uses
keep_whileconditions on bindings and auto-delete exchanges to let Khepri handle the deletion of semantically related tree nodes. RabbitMQ just has to make a simle "delete this queue" command.To maintain backward compatibility, we introduce the
replaced_delete_queue_transactionfeature flag. Itsenablecallback will take care of rewriting all bindings and auto-delete exchanges record in the store to add the newkeep_whileconditions.The binding deletion transaction is also simplified because it benefits from the
keep_whileconditions. We may be able to replace this transaction is the future as well in the same manner.This is an automatic backport of pull request #14902 done by Mergify.