61932cdf1d
Summary: The patch adds iterator support to the integrated BlobDB implementation. Whenever a blob reference is encountered during iteration, the corresponding blob is retrieved by calling `Version::GetBlob`, assuming the `expose_blob_index` (formerly `allow_blob`) flag is *not* set. (Note: the flag is set by the old stacked BlobDB implementation, which has its own blob file handling/blob retrieval logic.) In addition, `DBIter` now uniformly returns `Status::NotSupported` with the error message `"BlobDB does not support merge operator."` when encountering a blob reference while performing a merge (instead of potentially returning a message that implies the database should be opened using the stacked BlobDB's `Open`.) TODO: We can implement support for lazily retrieving the blob value (or in other words, bypassing the retrieval of blob values based on key) by extending the `Iterator` API with a new `PrepareValue` method (similarly to `InternalIterator`, which already supports lazy values). Pull Request resolved: https://github.com/facebook/rocksdb/pull/7731 Test Plan: `make check` Reviewed By: riversand963 Differential Revision: D25256293 Pulled By: ltamasi fbshipit-source-id: c39cd782011495a526cdff99c16f5fca400c4811
RocksDB: A Persistent Key-Value Store for Flash and RAM Storage
RocksDB is developed and maintained by Facebook Database Engineering Team. It is built on earlier work on LevelDB by Sanjay Ghemawat (sanjay@google.com) and Jeff Dean (jeff@google.com)
This code is a library that forms the core building block for a fast key-value server, especially suited for storing data on flash drives. It has a Log-Structured-Merge-Database (LSM) design with flexible tradeoffs between Write-Amplification-Factor (WAF), Read-Amplification-Factor (RAF) and Space-Amplification-Factor (SAF). It has multi-threaded compactions, making it especially suitable for storing multiple terabytes of data in a single database.
Start with example usage here: https://github.com/facebook/rocksdb/tree/master/examples
See the github wiki for more explanation.
The public interface is in include/. Callers should not include or
rely on the details of any other header files in this package. Those
internal APIs may be changed without warning.
Design discussions are conducted in https://www.facebook.com/groups/rocksdb.dev/ and https://rocksdb.slack.com/
License
RocksDB is dual-licensed under both the GPLv2 (found in the COPYING file in the root directory) and Apache 2.0 License (found in the LICENSE.Apache file in the root directory). You may select, at your option, one of the above-listed licenses.