[SERVER-6640] Strict balancing guarantees with sharding tags Created: 30/Jul/12  Updated: 06/Dec/22  Resolved: 07/Oct/16

Status: Closed
Project: Core Server
Component/s: Sharding
Affects Version/s: 2.2.0-rc0
Fix Version/s: None

Type: Improvement Priority: Major - P3
Reporter: Vadim Semenov Assignee: [DO NOT USE] Backlog - Sharding Team
Resolution: Duplicate Votes: 1
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Duplicate
is duplicated by SERVER-18361 Sharding "top" splits should respect ... Closed
Assigned Teams:
Sharding
Participants:
Case:

 Description   

In 2.2.0-rc0 tag aware sharding behaves strange: it doesn't offer strict guarantee to which chunk a document will be placed when inserted. So if we have 2 tags for 2 shards (e.g. 'US-West' and 'US-East') on an empty collection, inserting 2 documents which map to different tags will place both documents into one chunk; and the chunk location will depend on to which of the tags we've made insertion first. This behavior scales to any number of documents: there's always a high chance to have documents "misplaced" this way after automatic chunk splitting.



 Comments   
Comment by Kaloian Manassiev [ 07/Oct/16 ]

Please follow SERVER-18361 for more information on the fix for this bug.

Comment by Greg Studer [ 07/Mar/14 ]

Strict balancing guarantees aren't possible until the chunks are initially distributed, but agree the initial distribution should happen automatically when possible with tagged shards.

Generated at Thu Feb 08 03:12:17 UTC 2024 using Jira 9.7.1#970001-sha1:2222b88b221c4928ef0de3161136cc90c8356a66.