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Type:
Question
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Resolution: Fixed
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Priority:
Major - P3
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Affects Version/s: None
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Component/s: Integrations
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None
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(copied to CRM)
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None
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Fully Compatible
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Ruby Drivers
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Not Needed
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None
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None
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None
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None
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None
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None
MongoID produces incorrect results when connecting to a sharded cluster via an optimized SRV connection string. Specifically, warning messages suggest that the shard configuration is not persisted in the sharded cluster when using a load-balanced topology.
Warning Message:
W, [2025-05-16T05:32:41.600441 #824091] WARN -- : MONGOID: Product has shard config but is not persisted in a sharded cluster: #<Cluster topology=LoadBalanced[pl-0-ap-southeast-2.fp6lz.mongodb.net:1175] servers=[#<Server address=pl-0-ap-southeast-2.fp6lz.mongodb.net:1175 LB NO-MONITORING>]>
The issue can be reproduced on both MongoID versions 9.0.6 and 8.0.10.
Please confirm whether this behavior is caused by a defect in MongoID or a limitation in functionality that needs to be documented for users.
Reproduction Steps:
Testing Environment:
$ uname -a
Linux ip-172-31-2-67.ap-southeast-2.compute.internal 6.1.112-124.190.amzn2023.x86_64 #1 SMP PREEMPT_DYNAMIC Wed Oct 23 06:32:04 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux
$ ruby -v
ruby 3.1.0p0 (2021-12-25 revision fb4df44d16) [x86_64-linux]
Software versions:
- MongoDB: 8.0.9
- MongoID: 9.0.6 (confirmed reproduction on 8.0.10)
- Ruby Driver: 2.21.1
Gemfile:
cat > Gemfile <<EOF source 'https://rubygems.org' gem 'mongoid', '~> 9.0' gem 'rake' EOF
Install dependencies using:
bundle install --path vendor/bundle
Test Model:
mkdir -p app/models/ cat > app/models/product.rb <<EOF class Product include Mongoid::Document store_in collection: "products" field :sku, type: String field :name, type: String field :price, type: Float # Shard by SKU shard_key({ sku: 1 }) end EOF
MongoID Configuration File:
mkdir config
cat > config/mongoid.yml <<EOF
development:
clients:
default:
uri: "mongodb+srv://*****:*****@nycluster2-sharded-pl-0-lb.fp6lz.mongodb.net/test?tls=true"
options:
server_selection_timeout: 5
# uri: "mongodb+srv://****:****@nycluster2-sharded.fp6lz.mongodb.net/test?tls=true"
EOF
Rakefile:
cat > Rakefile <<EOF require 'mongoid' require 'mongoid/tasks/database' Mongoid.load!(File.join(__dir__, 'config', 'mongoid.yml'), :development) \$LOAD_PATH.unshift(File.expand_path("app/models", __dir__)) Dir.glob(File.join(__dir__, 'app', 'models', '**', '*.rb')).each do |file| require file end task :environment load 'mongoid/tasks/database.rake' EOF
Run the MongoID task:
bundle exec rake db:mongoid:shard_collections
Observed Results:
Case 1: Using Optimized SRV Connection String:
Connection URI:
uri: "mongodb+srv://*****:*****@cluster2-sharded-pl-0-lb.fp6lz.mongodb.net/test?tls=true"
Run the task:
$ bundle exec rake db:mongoid:shard_collections
W, [2025-05-16T03:19:43.992593 #998276|#998276] WARN – : MONGOID: Product has shard config but is not persisted in a sharded cluster: #<Cluster topology=LoadBalanced[pl-0-ap-southeast-2.fp6lz.mongodb.net:1175] servers=[#<Server address=pl-0-ap-southeast-2.fp6lz.mongodb.net:1175 LB NO-MONITORING>]>
Observed Warning:
MongoID does not persist the shard configuration in the cluster topology. Instead, it shows a load-balanced topology warning and no shard confirmation.
—
Case 2: Using Standard SRV Connection String:
Connection URI:
uri: "mongodb+srv://*****:*****@nycluster2-sharded.fp6lz.mongodb.net/test?tls=true"
Run the task:
$ bundle exec rake db:mongoid:shard_collections
I, [2025-05-16T03:17:45.701237 #998154|#998154] INFO – : MONGOID: test.products is already sharded for Product
Observed Result:
MongoID successfully detects that the test.products collection is already sharded for the Product model, and no warning is generated.
Conclusion:
The issue occurs when using the optimized SRV connection string, but there is no problem when using the legacy SRV or the standard connection string.