Foreword
MongoRocks 4.0 is coming! Major cloud providers / internal users of Internet companies / domestic RocksDB developers / friends who are not familiar with WiredTiger / open source technology enthusiasts come and pay attention.
Past and present
RocksDB is an excellent storage engine with highly adjustable parameters and extreme data compression ratio. RocksDB is very active in the country, and there are several storage systems based on the RocksDB engine in almost all major cloud companies / companies. Storage projects based on RocksDB at home and abroad are also springing up, such as TIKV / TIDB, TerarkDB, MyRocks, CockRoachDB, etc.
As the No. 1 document database in Nosql, MongoDB officially supports two engines, Mmap and WiredTiger. MongoRocks refers to the adaptation of MongoDB to the RocksDB engine. RocksDB's role in this is equivalent to Mmap and WiredTiger.
MongoDB 3.2 and MongoDB 3.4 series support the RocksDB engine, which was early completed by Facebook's RocksDB team and MongoDB's engineers, and was mainly maintained by the original Facebook's IgorCanadi and Percona's Igorsol. Major domestic cloud vendors also support the sale of MongoRocks engines. However, due to the introduction of MongoDB 4.0 multi-document transactions, the MongoDB code has undergone a huge refactoring. The introduction of MongoRocks 4.0 also encountered technical difficulties.
Not long ago, Chinese engineer wolfkdy submitted a mr of nearly 5,000 lines to the MongoRocks project. The mr review was completed by IgorCanadi and wolfkdy. The integration of the mr marks the advent of MongoRocks 4.0.
RocksDB vs WiredTiger
This article does not intend to compare its advantages and disadvantages, which is likely to cause drudgery. Just talk about what they have in common.
RocksDB and WiredTiger are excellent kvengine. Support mvcc function. It has a good text compression rate and good multi-core scalability. However, WiredTiger 3.0 supports the more cutting-edge Timestamp Ordering Transaction (T / O) technology, which RocksDB does not have, which is the main reason why MongoRocks 4.0 has been delayed. The main work of wolfkdy is to complete this part. There is not much introduction of T / O technology on the Internet. This MongoDB transaction, timestamp and mixed logic clock is a comparison of MongoDB multi-document transaction introduction. Ok.
Who is maintaining
MongoRocks 4.0 is built on the code of MongoDB 4.0.3. MongoDB 4.0.3 complies with the AGPL agreement. There is no special reason for choosing this version. The middle layer of the MongoDB 4.0 series is not very different.
With the launch of MongoRocks 4.0, wolfkdy became an owner of the MongoRocks project. As the Maintainer of the MongoRocks project, it continues to go on. It is worth mentioning that this also means that more and more outstanding Chinese engineers have better control over cutting-edge open source databases. This Chinese engineer wolfkdy is the database engineer of Huawei Cloud Nosql team-Kong Deyu. Kong Deyu is also a member of the MongoDB Chinese Community Organizing Committee and works with other MongoDB experts to build the MongoDB community platform.