Least outstanding connections load balancing can improve the load distribution between instances but for Pgcat it may also improve handling slow replicas that don't go completely down. With LoC, traffic will quickly move away from the slow replica without waiting for the replica to be banned.
If all replicas slow down equally (due to a bad query that is hitting all replicas), the algorithm will degenerate to Random Load Balancing (which is what we had in Pgcat until today).
This may also allow Pgcat to accommodate pools with differently-sized replicas.
* Changes shard struct to use vector of ServerConfig
* Adds to query router
* Change client disconnect with error message to warn instead of debug
* Add warning logs for clean up actions
* Add support for multi-database / multi-user pools
* Nothing
* cargo fmt
* CI
* remove test users
* rename pool
* Update tests to use admin user/pass
* more fixes
* Revert bad change
* Use PGDATABASE env var
* send server info in case of admin
* Support reloading the entire config (including sharding logic) without restart.
* Fix bug incorrectly handing error reporting when the shard is set incorrectly via SET SHARD TO command.
selected wrong shard and the connection keep reporting fatal #80.
* Fix total_received and avg_recv admin database statistics.
* Enabling the query parser by default.
* More tests.
* Allow to set shard and set sharding key without quotes
* cover it
* dont look for these in the middle of another query
* friendly regex
* its own response to set shard key
* Refactor query routing into its own module
* commments; tests; dead code
* error message
* safer startup
* hm
* dont have to be public
* wow
* fix ci
* ok
* nl
* no more silent errors
