Make autoIndex and autoCreate default to false if connection's read preference is 'secondary' or 'secondaryPreferred'

[chumager]

Do you want to request a feature or report a bug?
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What is the current behavior?
when I set the readPreference to secondayPreferred in my app I get a mongo error:

You have triggered an unhandledRejection, you may have forgotten to catch a Promise rejection:                                                                
MongoError: not master                                                                                                                                        
    at MessageStream.messageHandler (/home/jcmunoz/.yarn/berry/cache/mongodb-npm-3.6.0-1deea15e1a-3.zip/node_modules/mongodb/lib/cmap/connection.js:266:20)   
    at MessageStream.emit (events.js:314:20)                                                                                                                  
    at processIncomingData (/home/jcmunoz/.yarn/berry/cache/mongodb-npm-3.6.0-1deea15e1a-3.zip/node_modules/mongodb/lib/cmap/message_stream.js:144:12)        
    at MessageStream._write (/home/jcmunoz/.yarn/berry/cache/mongodb-npm-3.6.0-1deea15e1a-3.zip/node_modules/mongodb/lib/cmap/message_stream.js:42:5)         
    at writeOrBuffer (_stream_writable.js:352:12)                                                                                                             
    at MessageStream.Writable.write (_stream_writable.js:303:10)                                                                                              
    at TLSSocket.ondata (_stream_readable.js:713:22)                                                                                                          
    at TLSSocket.emit (events.js:314:20)                                                                                                                      
    at addChunk (_stream_readable.js:303:12)                                                                                                                  
    at readableAddChunk (_stream_readable.js:279:9)                                                                                                           
    at TLSSocket.Readable.push (_stream_readable.js:218:10)                                                                                                   
    at TLSWrap.onStreamRead (internal/stream_base_commons.js:188:23)                                                                                          

I tested it like in #9309 and it works fine, but as the stack doesn't provide any useful info I can't trace the error.
is there a way to increase the stack trace so I can figure out where is my problem?

If I avoid the readPreference config I works ok, and I made a little plugin in the pre /find/ hook to set the readPreference in the query and it also works fine, so obviously it's not a mongoose problem, but I can't trace it.

It should come from another module or an error from myself, but it's weird because the driver should take care of doing insert or updates in the primary and querying in secondary.
If the current behavior is a bug, please provide the steps to reproduce.

too much code involve...
What is the expected behavior?
To be able to trace the error so I can fix it.
What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version.
node: 14.8.0
mongoose: 5.10.2
mongodb atlas 4.2.8

[vkarpov15]

How are you setting the readPreference?

Also, can you make sure you didn't typo in your app, not "secondayPreferred"?

[chumager]

hi, in the URL: mongodb+srv://user:pass@srv/database?retryWrites=true&w=majority&readPreference=secondaryPreferred&maxStalenessSeconds=120

As my app has a lot of async functions, the logs get printed without any related sequence, and I don't write anything to the DB unless an endpoint send an insert or update.

It happens between the schema definition and the model creation, but AFAIK I could write into de DB without problems even if I set secondaryPreferred, the configuration name is readPreference so I don't know why it could happens.

Regards.

[vkarpov15]

Do your models define indexes? For example, do you use unique: true or index: true in your schema definitions?

[chumager]

Hi, yes indeed I've lots of unique and other indexes.

Regards.

[vkarpov15]

I'd disable autoIndex on this connection, mongoose.connect('mongodb+srv://user:pass@srv/database?retryWrites=true&w=majority&readPreference=secondaryPreferred&maxStalenessSeconds=120', { autoIndex: false })

That will prevent Mongoose from trying to build indexes on this connection. MongoDB won't let you build indexes when you're connected to a secondary, so that's the most likely cause of this error.

For a future release, we should consider making autoIndex default to false if the read preference is secondary or secondaryPreferred, to avoid errors like this.

[chumager]

Thanks for the advice, but in this case, how do I build an index if I'm connected with secondary or secondaryPreferred?

Please tell me if I'm wrong but AFAIK this setting is only for querying. Do you know if this behavior is from mongo driver or is from mongoose?

Regards.

[vkarpov15]

The MongoDB server doesn't allow you to build indexes or do anything other than read-only operations when you're connected to a secondary. This error is from the MongoDB server, not the MongoDB node driver or Mongoose.

[Rossh87]

@vkarpov15 Interested in a PR for this?

[vkarpov15]

@Rossh87 yes, please base the PR against the 6.0 branch.