[SERVER-38673] Re-enable sharded change streams update lookup tests that use last stable mongos version Created: 17/Dec/18  Updated: 29/Oct/23  Resolved: 30/Sep/19

Status: Closed
Project: Core Server
Component/s: Replication
Affects Version/s: None
Fix Version/s: 4.3.1

Type: Task Priority: Major - P3
Reporter: William Schultz (Inactive) Assignee: William Schultz (Inactive)
Resolution: Fixed Votes: 0
Labels: open_todo_in_code
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Depends
Backwards Compatibility: Fully Compatible
Sprint: Repl 2019-10-07
Participants:

 Description   

The following tests were disabled from running in the sharding_last_stable_mongos_and_mixed_shards because they run sharded lookup queries and will not work when mongos is running on a version that doesn't support speculative majority find queries:

jstests/sharding/change_stream_lookup_single_shard_cluster.js
jstests/sharding/change_stream_read_preference.js
jstests/sharding/change_stream_update_lookup_collation.js
jstests/sharding/change_streams_primary_shard_unaware.js

When all the backports for SERVER-37560 are complete, we can re-enable these tests.



 Comments   
Comment by Githook User [ 30/Sep/19 ]

Author:

{'name': 'William Schultz', 'username': 'will62794', 'email': 'william.schultz@mongodb.com'}

Message: SERVER-38673 Re-enable sharded change streams update lookup tests that use last stable mongos version
Branch: master
https://github.com/mongodb/mongo/commit/b205f38fc66719a74790c1276920ee89253fbd29

Comment by William Schultz (Inactive) [ 03/Sep/19 ]

judah.schvimer Yes.

Comment by Judah Schvimer [ 28/Aug/19 ]

william.schultz, is this ready to be done now?

Comment by William Schultz (Inactive) [ 02/May/19 ]

These tests were disabled in the suites that use a 4.0 mongoS and 4.2 mongoD. (or equivalently a 3.6 mongoS and 4.0 mongoDs on the 4.0 branch). In 4.2, we added a new argument "allowSpeculativeMajorityRead" to the find command, which is what allows 'find' commands to utilize speculative majority read concern on mongoD nodes. If the mongoS is running 4.0, though, it won't properly attach this flag when sending a 'find' command to a 4.2 shard for an update lookup query. So, the node will reject the query saying that "majority" read concern is not enabled (when EMRC=false). Presumably we should just consider this mixed version configuration as unsupported for speculative majority change streams. I'm not entirely sure what the precedent is in terms of other features that have added new required command flags that are unsupported by older mongoS versions. In 4.3, though, we should be able to re-enable these tests, once 4.2 becomes the 'last-stable' version.

Comment by Gregory McKeon (Inactive) [ 02/May/19 ]

tess.avitabile is this closeable, or will we need to do this in 4.3?

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