Details
-
Task
-
Resolution: Fixed
-
Major - P3
-
None
-
None
-
None
-
Fully Compatible
-
Sharding EMEA 2022-08-22
Description
In order to optimise the connections opened by a mongos process when a nss.watch() request is received, the config server will have to persist in a new collection (called config.placementHistory) historical metadata about which shards of the cluster were hosting one or more chunks of nss at a specific point in time.
The objectives of this ticket are:
- The encoding of the schema for config.placementHistory, defined as
{namespace: string, // references db or collectiontimestamp: Timestamp,shards: array<ShardId> // may be empty}
- The instantiation of config.placementHistory as part of the initialisation of the ShardingCatalogManager (with an index over namespace+timestamp).