Revision df38c1ce660628f05b4686eeaf0b548295ce7967 authored by Mike Kolupaev on 22 April 2019, 15:17:45 UTC, committed by Facebook Github Bot on 22 April 2019, 15:20:35 UTC
Summary: Introduce BlockBasedTableOptions::index_shortening to give users control on which key shortening techniques to be used in building index blocks. Before this patch, both separators and successor keys where shortened in indexes. With this patch, the default is set to kShortenSeparators to only shorten the separators. Since each index block has many separators and only one successor (last key), the change should not have negative impact on index block size. However it should prevent many unnecessary block loads where due to approximation introduced by shorted successor, seek would land us to the previous block and then fix it by moving to the next one. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5174 Differential Revision: D14884185 Pulled By: al13n321 fbshipit-source-id: 1b08bc8c03edcf09b6b8c16e9a7eea08ad4dd534
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ROCKSDB_LITE.md
# RocksDBLite
RocksDBLite is a project focused on mobile use cases, which don't need a lot of fancy things we've built for server workloads and they are very sensitive to binary size. For that reason, we added a compile flag ROCKSDB_LITE that comments out a lot of the nonessential code and keeps the binary lean.
Some examples of the features disabled by ROCKSDB_LITE:
* compiled-in support for LDB tool
* No backupable DB
* No support for replication (which we provide in form of TransactionalIterator)
* No advanced monitoring tools
* No special-purpose memtables that are highly optimized for specific use cases
* No Transactions
When adding a new big feature to RocksDB, please add ROCKSDB_LITE compile guard if:
* Nobody from mobile really needs your feature,
* Your feature is adding a lot of weight to the binary.
Don't add ROCKSDB_LITE compile guard if:
* It would introduce a lot of code complexity. Compile guards make code harder to read. It's a trade-off.
* Your feature is not adding a lot of weight.
If unsure, ask. :)
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