Documentation

This crate provides an API to work with immutable (string -> string) maps stored on disk. The main access method are iterators, but there's a simpler API, too.

The general process is

• Writing a table, using TableBuilder. The entries have to be added in sorted order. The data doesn't have to be written to disk; any type implementing Write works.
• Reading a table, using Table. Again, the source is generic; any type implementing Read + Seek can be used.

Note that the tables and some other structures are generic over the ordering of keys; usually you can just use StandardComparator, though.

With Options, you can influence some details of how tables are laid out on disk. Usually, you don't need to; just use the Options::default() value.

If there's data corruption in the files on disk, defective blocks will be skipped. How many entries a single block contains depends on the block size, which can be set in the Options struct.

This crate reuses code originally written for the persistence part of rusty-leveldb, a reimplementation of Google's LevelDB in Rust. That's the reason for the code being a bit more complicated than needed at some points.

With no compression on a tmpfs volume running on an idle Intel(R) Xeon(R) CPU E5-1650 v2 @ 3.50GHz processor, the benchmark shows that in tables of 10'000 entries of each 16 key bytes and 16 value bytes, this crate will

• read 5.3 million entries per second
• write 1.2 million entries per second

The performance for tables of different sizes may differ.

Checksum verification failures often stem from either corruption (obviously) or incompletely written or half-overwritten SSTable files.

Contributions are very welcome! Feel free to send pull requests.