This is the tenth release of Apache BookKeeper!
The 4.7.0 release incorporates hundreds of bug fixes, improvements, and features since previous major release, 4.6.0, which was released four months ago. It is a big milestone in Apache BookKeeper community - Yahoo branch is fully merged back to upstream, and Apache Pulsar (incubating) starts using official BookKeeper release for its upcoming 2.0 release.
It is also the first release of Apache DistributedLog after it is merged as sub modules of Apache BookKeeper.
Apache BookKeeper/DistributedLog users are encouraged to upgrade to 4.7.0. The technical details of this release are summarized below.
The main features in 4.7.0 cover are around following areas:
Here is a list of dependencies changed in 4.7.0:
DbLedgerStorage as a dependency of bookkeeper-server module.20.0 to 21.0.There are multiple new client features introduced in 4.7.0. Here are two highlighted features:
The new fluent style APi is evolving in 4.7.0. All the methods in handlers are now having both async and sync methods. See #1288 for more details
circe-checksum module is ported from Apache Pulsar to Apache BookKeeper, and CRC32C digest type is added as one digest type option. The JNI based CRC32C in circe-checksum module provides excellent performance than existing CRC32 digest type. Users are encouraged to start use CRC32C digest type.
X.509 certificates are introduced for TLS authentication. See #965 for more details.DbLedgerStorage is a new ledger storage that introduced by Yahoo and now fully merged into Apache BookKeeper. It is fully compatible for both v2 and v3 protocols and also support long polling. It uses RocksDB to store ledger index, which eliminates the needed of ledger index files and reduces the number of open file descriptors and the amount of random IOs can occurs during flushing ledger index.
New serviceUri based metadata API is introduced as BP-29. This metadata API provides the metadata abstraction over ledger manager, registration service, allowing plugin different type of data stores as the metadata service.
There are a lot for performance related bug fixes and improvements in 4.7.0. Some of the changes are highlighted as below:
There are are multiple new commands are added in BookieShell. Here are a few highlighted:
metaformat is deprecated with two new commands initnewcluster and nukeexistingcluster. This separation provides better operability and reduces mistakes.initbookie command is introduced for initializing a new bookie. bookieformat keeps serving as the purpose of reformatting a bookie.A new BookKeeper CLI is proposed in BP-27. Some commands are already ported to new bookkeeper CLI. The full list of shell commands will be fully ported to new bookkeeper CLI in next release.
Operations are improved around readonly mode for handling bookkeeper outage situation. New settings are introduce allow entry log creation, high priority writes even when bookies are readonly. See Upgrade Guide to learn all newly added settings.