Document Database Service

Document Database Service(aka dds) is an open source project born from HuaweiCloud's MongoDB service. The codebase is based on MongoDB-4.0.3, the latest 4.0 series which still follows AGPL license. There are several enhancements which are not supported in MongoDB community version.

Enhancements

AuditLog

As MongoDB Company does not release Auditing functionality in community version, almost all cloud providers have their own solutions for auditing. dds also provides s set of configurations for auditing. Generally, users can add lines below into mongodb's yaml configuration to enable auditing.

auditLog:
  authSuccess: true|false
  format: JSON
  opFilter: off|all|...
  path: /path/to/your/audit_log

For the details of configuring auditing parameters, please see Audit Configuration

QueryStage Memory Limit

Although MongoDB limited the memory used for wiredTiger/rocksDB engine. It sometimes may still OOM, that's because MongoDB's QueryStage does not have the global memory limit. Let's take an example, one user can use at most 32MB RAM. However, if 100 queries run the sort in parallel, that should be 3.2GB. Until Mongo4.0, there is no global limit for this. We added a suite of parameters to limit query stage memory usage in total. please see Query Memory limit Params for more details.

Default admin/rwuser/readonly user and the privilleges

https://github.com/hwCloudDBSDDS/dds/wiki/Builtin-Users-Roles

Mongos Auto Flush Router

When a database is dropped and re-created again without flushing all mongos routing, data may be inconsistent, this is a legacy problem of MongoDB, we handled this by Mongos-Automatic-Flush-Routing-Cache

Chinese full-text search

https://github.com/hwCloudDBSDDS/dds/wiki/Chinese-Full-Text-Search