geekgonecrazy
commented
5 years ago Based on dm conversation seems like this is related to readPreference=nearest in connection string Which is likely related to: #8064
Basically even with w=majority... if it writes and immediately reads... or gets event from oplog and happens to read from 3rd node that isn’t part of the “majority” too fast... the data won’t have replicated to that node yet.
If you can some how get write concern to a set of nodes... and then read from that same set of nodes.. you could probably keep reading from secondaries. See tag sets for more reading
engelgabriel
Description:
OpLog error in logs
Steps to reproduce:
Have a OpLog enabled RC instance
Expected behavior:
No errors in logs
Actual behavior:
This message repeats in the logs
Error in oplog callback TypeError: Cannot read property 'u' of undefined at ModelsBaseDb.RocketChat.models.Subscriptions.on (/app/bundle/programs/server/app/app.js:13272:58) at emitOne (events.js:116:13) at ModelsBaseDb.emit (events.js:211:7) at ModelsBaseDb.processOplogRecord (/app/bundle/programs/server/packages/rocketchat_lib.js:12178:12) at /app/bundle/programs/server/packages/mongo.js:1494:7 at runWithEnvironment (packages/meteor.js:1238:24) at Object.callback (packages/meteor.js:1251:14) at /app/bundle/programs/server/packages/ddp-server.js:2130:36 at Array.forEach (<anonymous>:null:null) at Function._.each._.forEach (packages/underscore.js:139:11) at DDPServer._Crossbar.fire (/app/bundle/programs/server/packages/ddp-server.js:2128:7) at /app/bundle/programs/server/packages/mongo.js:1719:26 at Meteor.EnvironmentVariable.EVp.withValue (packages/meteor.js:1186:12) at packages/meteor.js:502:25 at runWithEnvironment (packages/meteor.js:1238:24Server Setup Information:
Additional context
Error just shows up inside of the logs