Hello!
I want to use the Transactions with Sessions feature on the Mongoid, the officially supported object-document mapper (ODM) for MongoDB in Ruby.
To make this possible, I already did setup a Replica Set on my system, following this tutorial:
http://blog.rueckstiess.com/mtools/mlaunch.html
About the topology , I am currently using the default configuration of this tutorial => http://blog.rueckstiess.com/mtools/mlaunch.html
mlaunch --replicaset
Therefore, I am starting a replica set with (by default) 3 nodes on ports 27017 , 27018 , 27019 .
However, I am having some problems when I try to invoke sessions on the ruby code. The error message says: “A session was attempted to be used with a MongoDB server version that doesn’t support sessions. Sessions are supported in MongoDB server versions 3.6 and higher.”. However, when I call db.version() , I can see it is on version 4.2.3 already
- Steps to reproduce the error:
- Enter on rails console
rails c
- Try to execute this code
Project.with_session do |session|
session.start_transaction
Project.create!(name: 'Example')
session.commit_transaction
end
- The result here is the following error message
Mongoid::Errors::InvalidSessionUse:
message:
Sessions are not supported by the connected server(s).
summary:
A session was attempted to be used with a MongoDB server version that doesn't support sessions. Sessions are supported in MongoDB server versions 3.6 and higher.
resolution:
Verify that all servers in your deployment are at least version 3.6 or don't attempt to use sessions with older server versions.
from /Users/victor/.rvm/gems/ruby-2.6.5@pocket/gems/mongoid-7.0.5/lib/mongoid/clients/sessions.rb:98:in `rescue in with_session'
Caused by Mongo::Error::InvalidSession: Sessions are not supported by the connected servers.
from /Users/victor/.rvm/gems/ruby-2.6.5@pocket/gems/mongo-2.12.1/lib/mongo/client.rb:865:in `start_session'
Some additional infos…
- My Replica Sets setup
$ mlaunch list
PROCESS PORT STATUS PID
mongod 27017 running -
mongod 27018 running 33353
mongod 27019 running 33356
- My
mongoid.ymlfile config
development:
clients:
default:
database: pocket_api_development
hosts:
- "<%= ENV["MONGO_HOST"] %>:27017"
options:
user: 'root'
password: 'ri8Oogu6'
auth_source: admin
replica_set: replset
options:
test:
clients:
default:
database: pocket_api_test
hosts:
- "<%= ENV["MONGO_HOST"] %>:27017"
options:
read:
mode: :primary
max_pool_size: 1
user: 'root'
password: 'ri8Oogu6'
auth_source: admin
- The Storage Engines
mongo --port 27017
> db.serverStatus().storageEngine
{
"name" : "wiredTiger",
"supportsCommittedReads" : true,
"oldestRequiredTimestampForCrashRecovery" : Timestamp(0, 0),
"supportsPendingDrops" : true,
"dropPendingIdents" : NumberLong(0),
"supportsSnapshotReadConcern" : true,
"readOnly" : false,
"persistent" : true,
"backupCursorOpen" : false
}
mongo --port 27018
replset:PRIMARY> db.serverStatus().storageEngine
{
"name" : "wiredTiger",
"supportsCommittedReads" : true,
"oldestRequiredTimestampForCrashRecovery" : Timestamp(1595260796, 1),
"supportsPendingDrops" : true,
"dropPendingIdents" : NumberLong(0),
"supportsSnapshotReadConcern" : true,
"readOnly" : false,
"persistent" : true,
"backupCursorOpen" : false
}
mongo --port 27019
> db.serverStatus().storageEngine
{
"name" : "wiredTiger",
"supportsCommittedReads" : true,
"oldestRequiredTimestampForCrashRecovery" : Timestamp(0, 0),
"supportsPendingDrops" : true,
"dropPendingIdents" : NumberLong(0),
"supportsSnapshotReadConcern" : true,
"readOnly" : false,
"persistent" : true,
"backupCursorOpen" : false
}