Struct ReadOptions

pub struct ReadOptions { /* private fields */ }

Implementations

impl ReadOptions

pub fn fill_cache(&mut self, v: bool)

Specify whether the “data block”/“index block”/“filter block” read for this iteration should be cached in memory? Callers may wish to set this field to false for bulk scans.

Default: true

pub fn set_snapshot<T>(&mut self, snapshot: &T)

where T: ConstHandle<rocksdb_snapshot_t>,

Sets the snapshot which should be used for the read. The snapshot must belong to the DB that is being read and must not have been released.

pub fn set_iterate_upper_bound<K>(&mut self, key: K)

where K: AsRef<[u8]>,

Sets the upper bound for an iterator. The upper bound itself is not included on the iteration result.

pub fn set_iterate_lower_bound<K>(&mut self, key: K)

where K: AsRef<[u8]>,

Sets the lower bound for an iterator.

pub fn set_prefix_same_as_start(&mut self, v: bool)

Enforce that the iterator only iterates over the same prefix as the seek. This option is effective only for prefix seeks, i.e. prefix_extractor is non-null for the column family and total_order_seek is false. Unlike iterate_upper_bound, prefix_same_as_start only works within a prefix but in both directions.

Default: false

pub fn set_total_order_seek(&mut self, v: bool)

Enable a total order seek regardless of index format (e.g. hash index) used in the table. Some table format (e.g. plain table) may not support this option.

If true when calling Get(), we also skip prefix bloom when reading from block based table. It provides a way to read existing data after changing implementation of prefix extractor.

pub fn set_readahead_size(&mut self, v: usize)

If non-zero, an iterator will create a new table reader which performs reads of the given size. Using a large size (> 2MB) can improve the performance of forward iteration on spinning disks. Default: 0

use ckb_rocksdb::{ReadOptions};

let mut opts = ReadOptions::default();
opts.set_readahead_size(4_194_304); // 4mb

pub fn set_async_io(&mut self, v: bool)

Asynchronously prefetch some data.

Used for sequential reads and internal automatic prefetching.

Default: false

pub fn input_or_default( input: Option<&ReadOptions>, default_readopts: &mut Option<ReadOptions>, ) -> Result<*mut rocksdb_readoptions_t, Error>

Trait Implementations

impl<T> BatchedMultiGetCF<ReadOptions> for T

where T: Handle<rocksdb_t> + Read,

fn batched_multi_get_cf_full<'a, K, I>( &self, cf: &ColumnFamily, keys: I, sorted_input: bool, readopts: Option<&ReadOptions>, ) -> Vec<Result<Option<DBPinnableSlice<'_>>, Error>>

where K: AsRef<[u8]> + 'a + ?Sized, I: IntoIterator<Item = &'a K>,

fn batched_multi_get_cf<'a, K, I>( &self, cf: &ColumnFamily, keys: I, sorted_input: bool, ) -> Vec<Result<Option<DBPinnableSlice<'_>>, Error>>

where K: AsRef<[u8]> + 'a + ?Sized, I: IntoIterator<Item = &'a K>,

fn batched_multi_get_cf_opt<'a, K, I>( &self, cf: &ColumnFamily, keys: I, sorted_input: bool, readopts: &R, ) -> Vec<Result<Option<DBPinnableSlice<'_>>, Error>>

where K: AsRef<[u8]> + 'a + ?Sized, I: IntoIterator<Item = &'a K>,

impl Clone for ReadOptions

fn clone(&self) -> ReadOptions

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Default for ReadOptions

fn default() -> ReadOptions

Returns the “default value” for a type.

impl Drop for ReadOptions

fn drop(&mut self)

Executes the destructor for this type.

impl<T> GetCF<ReadOptions> for T

where T: Handle<rocksdb_t> + Read,

fn get_cf_full<K>( &self, cf: Option<&ColumnFamily>, key: K, readopts: Option<&ReadOptions>, ) -> Result<Option<DBVector>, Error>

where K: AsRef<[u8]>,

fn get_cf<K>( &self, cf: &ColumnFamily, key: K, ) -> Result<Option<DBVector>, Error>

where K: AsRef<[u8]>,

fn get_cf_opt<K>( &self, cf: &ColumnFamily, key: K, readopts: &R, ) -> Result<Option<DBVector>, Error>

where K: AsRef<[u8]>,

impl Handle<rocksdb_readoptions_t> for ReadOptions

fn handle(&self) -> *mut rocksdb_readoptions_t

impl<T> MultiGet<ReadOptions> for T

where T: Handle<rocksdb_t> + Read,

fn multi_get_full<K, I>( &self, keys: I, readopts: Option<&ReadOptions>, ) -> Vec<Result<Option<DBVector>, Error>>

where K: AsRef<[u8]>, I: IntoIterator<Item = K>,

Return the values associated with the given keys using read options.

fn multi_get<K, I>(&self, keys: I) -> Vec<Result<Option<DBVector>, Error>>

where K: AsRef<[u8]>, I: IntoIterator<Item = K>,

fn multi_get_opt<K, I>( &self, keys: I, readopts: &R, ) -> Vec<Result<Option<DBVector>, Error>>

where K: AsRef<[u8]>, I: IntoIterator<Item = K>,

impl<T> MultiGetCF<ReadOptions> for T

where T: Handle<rocksdb_t> + Read,

fn multi_get_cf_full<'a, K, I>( &self, keys: I, readopts: Option<&ReadOptions>, ) -> Vec<Result<Option<DBVector>, Error>>

where K: AsRef<[u8]>, I: IntoIterator<Item = (&'a ColumnFamily, K)>,

Return the values associated with the given keys and column families using read options.

fn multi_get_cf<'a, K, I>( &self, keys_cf: I, ) -> Vec<Result<Option<DBVector>, Error>>

where K: AsRef<[u8]>, I: IntoIterator<Item = (&'a ColumnFamily, K)>,

fn multi_get_cf_opt<'a, K, I>( &self, keys_cf: I, readopts: &R, ) -> Vec<Result<Option<DBVector>, Error>>

where K: AsRef<[u8]>, I: IntoIterator<Item = (&'a ColumnFamily, K)>,

impl Send for ReadOptions

impl Sync for ReadOptions