[SERVER-73937] Remove special case for config.collections in sharded_agg_helpers when catalog shard feature flag is enabled Created: 13/Feb/23  Updated: 29/Oct/23  Resolved: 18/Feb/23

Status: Closed
Project: Core Server
Component/s: None
Affects Version/s: None
Fix Version/s: 7.0.0-rc0

Type: Task Priority: Major - P3
Reporter: Jack Mulrow Assignee: Jack Mulrow
Resolution: Fixed Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Backwards Compatibility: Fully Compatible
Sprint: Sharding NYC 2023-02-20
Participants:

 Description   

The attachCursorToPipeline() helper in sharded_agg_helpers.cpp will skip the unsharded collection targeting path if the collection is "config.collections" and will merge a lookup pipeline targeting that collection on "any" shard instead of the primary shard. This was added in SERVER-67891 likely because the $lookup used by $shardedDataDistribution reads from a config server collection, but wants to join with data from other collections, which the config server didn't have logic to support because it uses the NonShardServerProcessInterface for aggregations. PM-2290 makes config servers use the regular shard server process interface, so this logic should be unnecessary and can be removed if the cluster is in a high enough FCV (to guarantee the config server is in the latest binary).



 Comments   
Comment by Githook User [ 17/Feb/23 ]

Author:

{'name': 'Jack Mulrow', 'email': 'jack.mulrow@mongodb.com', 'username': 'jsmulrow'}

Message: SERVER-73937 Remove config.collections sharded agg special case
Branch: master
https://github.com/mongodb/mongo/commit/f5e898b99476ff43e8afcfefdb4df646535ae13b

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