emqx/changes/v5.0.24.en.md

# v5.0.24

## Enhancements

- [#10457](https://github.com/emqx/emqx/pull/10457) Deprecates the integration with StatsD.

  There seemd to be no user using StatsD integration, so we have decided to hide this feature
  for now. We will either remove or revive it based on requirements in the future.

- [#10458](https://github.com/emqx/emqx/pull/10458) Set the level of plugin configuration options to low level,
  in most cases, users only need to manage plugins on the dashboard
  without the need for manual modification, so we lowered the level.

- [#10491](https://github.com/emqx/emqx/pull/10491) Rename `etcd.ssl` to `etcd.ssl_options` to keep all of SSL options consistent in the configuration file.

- [#10512](https://github.com/emqx/emqx/pull/10512) Improved the storage format of Unicode characters in data files,
  Now we can store Unicode characters normally.
  For example: "SELECT * FROM \"t/1\" WHERE clientid = \"-测试专用-\""

- [#10487](https://github.com/emqx/emqx/pull/10487) Optimize the instance of limiter for whose rate is `infinity` to reduce memory and CPU usage.

- [#10490](https://github.com/emqx/emqx/pull/10490) Remove the default limit of connect rate which used to be `1000/s`

## Bug Fixes

- [#10407](https://github.com/emqx/emqx/pull/10407) Improve 'emqx_alarm' performance by using Mnesia dirty operations and avoiding
  unnecessary calls from 'emqx_resource_manager' to reactivate alarms that have been already activated.
  Use new safe 'emqx_alarm' API to activate/deactivate alarms to ensure that emqx_resource_manager
  doesn't crash because of alarm timeouts.
  The crashes were possible when the following conditions co-occurred:
  - a relatively high number of failing resources, e.g. bridges tried to activate alarms on re-occurring errors;
  - the system experienced a very high load.

- [#10420](https://github.com/emqx/emqx/pull/10420) Fix HTTP path handling when composing the URL for the HTTP requests in authentication and authorization modules.
  * Avoid unnecessary URL normalization since we cannot assume that external servers treat original and normalized URLs equally. This led to bugs like [#10411](https://github.com/emqx/emqx/issues/10411).
  * Fix the issue that path segments could be HTTP encoded twice.

- [#10422](https://github.com/emqx/emqx/pull/10422) Fixed a bug where external plugins could not be configured via environment variables in a lone-node cluster.

- [#10448](https://github.com/emqx/emqx/pull/10448) Fix a compatibility issue of limiter configuration introduced by v5.0.23 which broke the upgrade from previous versions if the `capacity` is `infinity`.

  In v5.0.23 we have replaced `capacity` with `burst`. After this fix, a `capacity = infinity` config will be automatically converted to equivalent `burst = 0`.

- [#10449](https://github.com/emqx/emqx/pull/10449) Validate the ssl_options and header configurations when creating authentication http (`authn_http`).
  Prior to this, incorrect `ssl` configuration could result in successful creation but the entire authn being unusable.

- [#10455](https://github.com/emqx/emqx/pull/10455) Fixed an issue that could cause (otherwise harmless) noise in the logs.

  During some particularly slow synchronous calls to bridges, some late replies could be sent to connections processes that were no longer expecting a reply, and then emit an error log like:

  ```
  2023-04-19T18:24:35.350233+00:00 [error] msg: unexpected_info, mfa: emqx_channel:handle_info/2, line: 1278, peername: 172.22.0.1:36384, clientid: caribdis_bench_sub_1137967633_4788, info: {#Ref<0.408802983.1941504010.189402>,{ok,200,[{<<"cache-control">>,<<"max-age=0, ...">>}}
  ```

  Those logs are harmless, but they could flood and worry the users without need.

- [#10462](https://github.com/emqx/emqx/pull/10462) Deprecate config `broker.shared_dispatch_ack_enabled`.
  This was designed to avoid dispatching messages to a shared-subscription session which has the client disconnected.
  However since v5.0.9, this feature is no longer useful because the shared-subscrption messages in a expired session will be redispatched to other sessions in the group.
  See also: https://github.com/emqx/emqx/pull/9104

- [#10463](https://github.com/emqx/emqx/pull/10463) Improve bridges API error handling.
  If Webhook bridge URL is not valid, bridges API will return '400' error instead of '500'.

- [#10484](https://github.com/emqx/emqx/pull/10484) Fix the issue that the priority of the configuration cannot be set during rolling upgrade.
  For example, when authorization is modified in v5.0.21 and then upgraded v5.0.23 through rolling upgrade,
  the authorization will be restored to the default.

- [#10495](https://github.com/emqx/emqx/pull/10495) Add the limiter API `/configs/limiter` which was deleted by mistake back.

- [#10500](https://github.com/emqx/emqx/pull/10500) Add several fixes, enhancements and features in Mria:
  - protect `mria:join/1,2` with a global lock to prevent conflicts between
  two nodes trying to join each other simultaneously
  [Mria PR](https://github.com/emqx/mria/pull/137)
  - implement new function `mria:sync_transaction/4,3,2`, which blocks the caller until
  a transaction is imported to the local node (if the local node is a replicant, otherwise,
  it behaves exactly the same as `mria:transaction/3,2`)
  [Mria PR](https://github.com/emqx/mria/pull/136)
  - optimize `mria:running_nodes/0`
  [Mria PR](https://github.com/emqx/mria/pull/135)
  - optimize `mria:ro_transaction/2` when called on a replicant node
  [Mria PR](https://github.com/emqx/mria/pull/134).

- [#10518](https://github.com/emqx/emqx/pull/10518) Add the following fixes and features in Mria:
  - call `mria_rlog:role/1` safely in mria_membership to ensure that mria_membership
  gen_server won't crash if RPC to another node fails
  [Mria PR](https://github.com/emqx/mria/pull/139)
  - Add extra field to ?rlog_sync table to facilitate extending this functionality in future
  [Mria PR](https://github.com/emqx/mria/pull/138).