Struct Config 

pub struct Config {

    pub level_count: u8,
    pub data_block_compression_policy: CompressionPolicy,
    pub index_block_compression_policy: CompressionPolicy,
    pub data_block_restart_interval_policy: RestartIntervalPolicy,
    pub index_block_restart_interval_policy: RestartIntervalPolicy,
    pub data_block_size_policy: BlockSizePolicy,
    pub index_block_size_policy: BlockSizePolicy,
    pub index_block_pinning_policy: PinningPolicy,
    pub filter_block_pinning_policy: PinningPolicy,
    pub top_level_index_block_pinning_policy: PinningPolicy,
    pub top_level_filter_block_pinning_policy: PinningPolicy,
    pub data_block_hash_ratio_policy: HashRatioPolicy,
    pub index_block_partitioning_policy: PartioningPolicy,
    pub filter_block_partitioning_policy: PartioningPolicy,
    pub index_block_partition_size_policy: BlockSizePolicy,
    pub filter_block_partition_size_policy: BlockSizePolicy,
    pub filter_policy: FilterPolicy,
    /* private fields */
}

Tree configuration builder

Fields

level_count: u8

Number of levels of the LSM tree (depth of tree)

Once set, the level count is fixed (in the “manifest” file)

data_block_compression_policy: CompressionPolicy

What type of compression is used for data blocks

index_block_compression_policy: CompressionPolicy

What type of compression is used for index blocks

data_block_restart_interval_policy: RestartIntervalPolicy

Restart interval inside data blocks

index_block_restart_interval_policy: RestartIntervalPolicy

Restart interval inside index blocks

data_block_size_policy: BlockSizePolicy

Block size of data blocks

index_block_size_policy: BlockSizePolicy

Block size of index blocks

index_block_pinning_policy: PinningPolicy

Whether to pin index blocks

filter_block_pinning_policy: PinningPolicy

Whether to pin filter blocks

top_level_index_block_pinning_policy: PinningPolicy

Whether to pin top level index of partitioned index

top_level_filter_block_pinning_policy: PinningPolicy

Whether to pin top level index of partitioned filter

data_block_hash_ratio_policy: HashRatioPolicy

Data block hash ratio

index_block_partitioning_policy: PartioningPolicy

Whether to partition index blocks

filter_block_partitioning_policy: PartioningPolicy

Whether to partition filter blocks

index_block_partition_size_policy: BlockSizePolicy

Partition size when using partitioned indexes

filter_block_partition_size_policy: BlockSizePolicy

Partition size when using partitioned filters

filter_policy: FilterPolicy

Filter construction policy

Implementations

impl Config

pub fn new<P: AsRef<Path>>(path: P) -> Self

Initializes a new config

pub fn use_cache(self, cache: Arc<Cache>) -> Self

Sets the global cache.

You can create a global Cache and share it between multiple trees to cap global cache memory usage.

Defaults to a cache with 16 MiB of capacity per tree.

pub fn expect_point_read_hits(self, b: bool) -> Self

If true, the last level will not build filters, reducing the filter size of a database by ~90% typically.

Enable this only if you know that point reads generally are expected to find a key-value pair.

pub fn filter_block_partitioning_policy(self, policy: PinningPolicy) -> Self

Sets the partitioning policy for filter blocks.

pub fn index_block_partitioning_policy(self, policy: PinningPolicy) -> Self

Sets the partitioning policy for index blocks.

pub fn filter_block_pinning_policy(self, policy: PinningPolicy) -> Self

Sets the pinning policy for filter blocks.

pub fn index_block_pinning_policy(self, policy: PinningPolicy) -> Self

Sets the pinning policy for index blocks.

pub fn data_block_restart_interval_policy( self, policy: RestartIntervalPolicy, ) -> Self

Sets the restart interval inside data blocks.

A higher restart interval saves space while increasing lookup times inside data blocks.

Default = 16

pub fn filter_policy(self, policy: FilterPolicy) -> Self

Sets the filter construction policy.

pub fn data_block_compression_policy(self, policy: CompressionPolicy) -> Self

Sets the compression method for data blocks.

pub fn index_block_compression_policy(self, policy: CompressionPolicy) -> Self

Sets the compression method for index blocks.

pub fn data_block_size_policy(self, policy: BlockSizePolicy) -> Self

Sets the data block size policy.

pub fn data_block_hash_ratio_policy(self, policy: HashRatioPolicy) -> Self

Sets the hash ratio policy for data blocks.

If greater than 0.0, a hash index is embedded into data blocks that can speed up reads inside the data block.

pub fn with_kv_separation(self, opts: Option<KvSeparationOptions>) -> Self

Toggles key-value separation.

pub fn open(self) -> Result<AnyTree>

Opens a tree using the config.

Errors

Will return Err if an IO error occurs.

Trait Implementations

impl Clone for Config

fn clone(&self) -> Config

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Default for Config

fn default() -> Self

Returns the “default value” for a type.