[DOCS-14602] [SERVER] Incomplete information about role of heartbeats in replication lag calculation Created: 25/Jun/21 Updated: 30/Oct/23 |
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| Status: | Closed |
| Project: | Documentation |
| Component/s: | manual, Server |
| Affects Version/s: | 4.4 |
| Fix Version/s: | Server_Docs_20231030 |
| Type: | Improvement | Priority: | Major - P3 |
| Reporter: | Przemek Malkowski | Assignee: | Unassigned |
| Resolution: | Won't Do | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Participants: | |
| Days since reply: | 1 year, 14 weeks, 2 days ago |
| Epic Link: | DOCSP-11702 |
| Description |
DescriptionThe rs.printSecondaryReplicationInfo() function is supposed to return information how far the secondaries behind the replica. Also db.printReplicationInfo() shows the last timestamp from the oplog, and apparently both use the same time. During the idle time when no new data is written, this is supposed to rely on hearbeats sent from primary to secondaries, if I read the comment from: https://docs.mongodb.com/manual/reference/method/rs.printSecondaryReplicationInfo/ correctly:
Now, although the https://docs.mongodb.com/manual/reference/replica-configuration/#mongodb-rsconf-rsconf.settings.heartbeatIntervalMillis is set to 2 seconds, the timestamps in the functions I mentioned above, are updated only every 10 seconds rather:
the below two were obtained <1s apart:
Not only it makes the function often return false 10 secs behind value, but limits the lag checking to only every 10 seconds. Which setting controls the heartbeats frequency for these functions? Is it adjustable? Scope of changesImpact to Other DocsMVP (Work and Date)Resources (Scope or Design Docs, Invision, etc.) |
| Comments |
| Comment by Education Bot [ 31/Oct/22 ] |
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Hello! This ticket has been closed due to inactivity. If you believe this ticket is still important, please reopen it and leave a comment to explain why. Thank you! |