[SERVER-27446] operation_latency_histogram.js fails in initial sync passthrough due to reads performed by the repl system Created: 16/Dec/16  Updated: 05/Apr/17  Resolved: 16/Dec/16

Status: Closed
Project: Core Server
Component/s: Querying, Replication
Affects Version/s: None
Fix Version/s: 3.4.2, 3.5.2

Type: Bug Priority: Major - P3
Reporter: David Storch Assignee: David Storch
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Backports
Depends
Related
is related to SERVER-25068 Make small_oplog_rs_initsync passthro... Closed
Backwards Compatibility: Fully Compatible
Operating System: ALL
Backport Requested:
v3.4
Sprint: Query 2017-01-23
Participants:
Linked BF Score: 0

 Description   

The operation_latency_histogram.js integration test makes assertions about the number of read and write operations performed against a particular collection in order to test the new latencyStats() feature available in version 3.4. In particular, it writes to a collection and ensures the latency stats reflect the correct count of write operations, but that the number of read operations has not changed (aside from the read done to retrieve the latency stats themselves).

The assumption that the number of read operations has not changed, however, is invalid in our initial sync passthrough suite, core_small_oplog_rs_initsync. When an initial sync occurs during the execution of the test, the downstream node will issue a find command against its sync source in order to clone the data. From the sync source's perspective, this read looks just like any user-issued find, and it will be counted by the operation latency histogram. This causes the read count to be higher than expected by the test.



 Comments   
Comment by Githook User [ 21/Dec/16 ]

Author:

{u'username': u'dstorch', u'name': u'David Storch', u'email': u'david.storch@10gen.com'}

Message: SERVER-27446 blacklist operation_latency_histogram.js from background initial sync passthroughs

(cherry picked from commit 530418b23c4c9d45cde993853967fe1b7b636c47)
Branch: v3.4
https://github.com/mongodb/mongo/commit/b9c5e101e43a6aae2d3ee56206492c1df0b960cf

Comment by Githook User [ 16/Dec/16 ]

Author:

{u'username': u'dstorch', u'name': u'David Storch', u'email': u'david.storch@10gen.com'}

Message: SERVER-27446 blacklist operation_latency_histogram.js from background initial sync passthroughs
Branch: master
https://github.com/mongodb/mongo/commit/530418b23c4c9d45cde993853967fe1b7b636c47

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