Percona Server for MongoDB is an enhanced, open source, and highly-scalable database that is a fully-compatible, drop-in replacement for MongoDB 3.6 Community Edition. It supports MongoDB 3.6 protocols and drivers.
Percona Server for MongoDB extends MongoDB Community Edition functionality by including the Percona Memory Engine, as well as several enterprise-grade features. Percona Server for MongoDB requires no changes to MongoDB applications or code.
This release is based on MongoDB 3.6.3 and includes the following additional changes:
MongoRocks is deprecated in Percona Server for MongoDB 3.6 and it will be fully removed in the next major version of Percona Server for MongoDB. Feature compatibility version is set to 3.4 when using Percona Server for MongoDB 3.6 with MongoRocks, so 3.6 features, such as retryable writes and causal consistency, cannot be used. Additionally, read concern majority may produce unreliable results.
#PSMDB-191: Fixed a bug in MongoRocks engine initialization code which caused wrong initialization of _maxPrefix value. This could lead to reuse of dropped prefix and accidental removal of data from the collection using a reused prefix.
In some specific conditions data records could disappear at an arbitrary moment of time from the collections or indexes created after server restart. This could happen as the result of the following sequence of events: [LIST=1]
User deletes one or more indexes or collections. These should be the ones using maximum existing prefixes values.
User shuts down the server before MongoRocks compaction thread executes compactions of deleted ranges.
User restarts the server and creates new collections. Due to the bug those new collections and their indexes may get the same prefix values which were deleted and not yet compacted. The user inserts some data into the new collections.
After the server restart MongoRocks compaction thread continues executing compactions of the deleted ranges and this process may eventually delete data from the collections sharing prefixes with deleted ranges.
[*]#PSMDB-178: RocksSnapshotManager was reworked to match the new model of interaction between MongoDB and storage engine’s snapshot manager.
The Percona Server for MongoDB 3.6.3-1.1 release notes are available in the official documentation.