| # PIP-119: Enable consistent hashing by default on KeyShared dispatcher |
| |
| The consistent hashing implementation to uniformly assign keys to consumers |
| in the context of a KeyShared subscription, was introduced in |
| https://github.com/apache/pulsar/pull/6791, which was released in Pulsar 2.6.0. |
| |
| While consistent hashing can use slightly more memory in certain cases, it is |
| more suitable as a general default implementation, as it leads to a fairer |
| distribution of keys across consumers, and avoiding corner cases that depend |
| on the sequence of addition/removal of consumers. |
| |
| ## Proposed changes |
| |
| In 2.10 release, for the setting: |
| |
| ```properties |
| # On KeyShared subscriptions, with default AUTO_SPLIT mode, use splitting ranges or |
| # consistent hashing to reassign keys to new consumers |
| subscriptionKeySharedUseConsistentHashing=false |
| ``` |
| |
| Change its default value to `true`. |
| |
| The `AUTO_SPLIT` mode will not be removed nor deprecated. Users will still be |
| able to use the old implementation. |
