Struct rocks::universal_compaction::CompactionOptionsUniversal

pub struct CompactionOptionsUniversal { /* fields omitted */ }

Implementations

impl CompactionOptionsUniversal

pub fn size_ratio(self, val: u32) -> Self

Percentage flexibilty while comparing file size. If the candidate file(s) size is 1% smaller than the next file's size, then include next file into this candidate set.

Default: 1

pub fn min_merge_width(self, val: u32) -> Self

The minimum number of files in a single compaction run.

Default: 2

pub fn max_merge_width(self, val: u32) -> Self

The maximum number of files in a single compaction run. Default: UINT_MAX

pub fn max_size_amplification_percent(self, val: u32) -> Self

The size amplification is defined as the amount (in percentage) of additional storage needed to store a single byte of data in the database. For example, a size amplification of 2% means that a database that contains 100 bytes of user-data may occupy upto 102 bytes of physical storage. By this definition, a fully compacted database has a size amplification of 0%. Rocksdb uses the following heuristic to calculate size amplification: it assumes that all files excluding the earliest file contribute to the size amplification.

Default: 200, which means that a 100 byte database could require upto 300 bytes of storage.

pub fn compression_size_percent(self, val: i32) -> Self

If this option is set to be -1 (the default value), all the output files will follow compression type specified.

If this option is not negative, we will try to make sure compressed size is just above this value. In normal cases, at least this percentage of data will be compressed.

When we are compacting to a new file, here is the criteria whether it needs to be compressed: assuming here are the list of files sorted by generation time:

A1...An B1...Bm C1...Ct

where A1 is the newest and Ct is the oldest, and we are going to compact B1...Bm, we calculate the total size of all the files as total_size, as well as the total size of C1...Ct as total_C, the compaction output file will be compressed iff

total_C / total_size < this percentage

Default: -1

pub fn stop_style(self, val: CompactionStopStyle) -> Self

The algorithm used to stop picking files into a single compaction run Default: kCompactionStopStyleTotalSize

pub fn allow_trivial_move(self, val: bool) -> Self

Option to optimize the universal multi level compaction by enabling trivial move for non overlapping files. Default: false

Trait Implementations

impl Default for CompactionOptionsUniversal

pub fn default() -> Self

Returns the "default value" for a type.

impl Drop for CompactionOptionsUniversal

pub fn drop(&mut self)

Executes the destructor for this type.