mongodb returning error using $out with mongos

1
votes

I have a mongodb cluster containing two shards, each a replication set of 3 nodes, and a config server cluster again with three nodes.

All seems to be in order apart from when I attempt to write a collection at the end of an aggregation pipeline using the $out operator:

db.getCollection('restaurants').aggregate([
 {$match : {$text : {$search : "steak"}}},
 {$out : "steak_restaurants"}
])

This is return the following error:

ailed to execute script.

Error: Assert: command failed: { "ok" : 0, "errmsg" : "listIndexes failed: { ok: 0.0, errmsg: \"not master and slaveOk=false\", code: 13435, codeName: \"NotMasterNoSlaveOk\" }", "code" : 18631, "codeName" : "Location18631" } : aggregate failed _getErrorWithCode@src/mongo/shell/utils.js:25:13 doassert@src/mongo/shell/assert.js:16:14 assert.commandWorked@src/mongo/shell/assert.js:370:5 DBCollection.prototype.aggregate@src/mongo/shell/collection.js:1319:5 @(shell):1:1

Error: command failed: { "ok" : 0, "errmsg" : "listIndexes failed: { ok: 0.0, errmsg: \"not master and slaveOk=false\", code: 13435, codeName: \"NotMasterNoSlaveOk\" }", "code" : 18631, "codeName" : "Location18631" } : aggregate failed : _getErrorWithCode@src/mongo/shell/utils.js:25:13 doassert@src/mongo/shell/assert.js:16:14 assert.commandWorked@src/mongo/shell/assert.js:370:5 DBCollection.prototype.aggregate@src/mongo/shell/collection.js:1319:5 @(shell):1:1

The mongo shell is connected to a mongos router. If I execute the same against mongod, this works fine.

The error suggests that somehow reading is taking place from a secondary, however, I have not set any read preference and I would have thought that mongos would resolve the primary correctly by itself. Any ideas or insight please?

2
mongodb
Are you certain about your connection? Can you demonstrate how you are connecting and the available nodes? Because the error does indeed suggest that you are in fact connected to a secondary node, and it is of course only possible to use $out when connected to a primary. – Neil Lunn
Appears to only be occurring when executed through Robo 3T. Executing through a raw shell works fine. – Ellis

2 Answers

1
votes

Appears to only be occurring when executed through Robo 3T. Executing through a raw shell works fine.

0
votes

I had the same problem today and solved it by removing the "getCollection".

Can you try running:

   db.restaurants.aggregate([
   {$match : {$text : {$search : "steak"}}},
   {$out : "steak_restaurants"}
   ])