Struct tiny_lsm::Lsm [−][src]
Implementations
Recover the LSM off disk. Make sure to never recover a DB using different K, V parameters than it was created with, or there may be data loss.
This is an O(N) operation and involves reading
all previously written sstables and the log,
to recover all data into an in-memory BTreeMap.
Recover the LSM, and provide custom options
around IO and merging. All values in the Config
object are safe to change across restarts, unlike
the fixed K and V lengths for data in the database.
Writes a KV pair into the Lsm, returning the
previous value if it existed. This operation might
involve blocking for a very brief moment as a 32kb
BufWriter wrapping the log file is flushed.
If you require blocking until all written data is
durable, use the Lsm::flush method below.
Removes a KV pair from the Lsm, returning the
previous value if it existed. This operation might
involve blocking for a very brief moment as a 32kb
BufWriter wrapping the log file is flushed.
If you require blocking until all written data is
durable, use the Lsm::flush method below.
Apply a set of updates to the Lsm and
log them to disk in a way that will
be recovered only if every update is
present.
Blocks until all log data has been written out to disk and fsynced. If the log file has grown above a certain threshold, it will be compacted into a new sstable and the log file will be truncated after the sstable has been written, fsynced, and the sstable directory has been fsyced.
Methods from Deref<Target = BTreeMap<[u8; K], [u8; V]>>
Returns a reference to the value corresponding to the key.
The key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.
Examples
Basic usage:
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "a");
assert_eq!(map.get(&1), Some(&"a"));
assert_eq!(map.get(&2), None);Returns the key-value pair corresponding to the supplied key.
The supplied key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.
Examples
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "a");
assert_eq!(map.get_key_value(&1), Some((&1, &"a")));
assert_eq!(map.get_key_value(&2), None);🔬 This is a nightly-only experimental API. (map_first_last)
map_first_last)Returns the first key-value pair in the map. The key in this pair is the minimum key in the map.
Examples
Basic usage:
#![feature(map_first_last)]
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
assert_eq!(map.first_key_value(), None);
map.insert(1, "b");
map.insert(2, "a");
assert_eq!(map.first_key_value(), Some((&1, &"b")));🔬 This is a nightly-only experimental API. (map_first_last)
map_first_last)Returns the last key-value pair in the map. The key in this pair is the maximum key in the map.
Examples
Basic usage:
#![feature(map_first_last)]
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "b");
map.insert(2, "a");
assert_eq!(map.last_key_value(), Some((&2, &"a")));Returns true if the map contains a value for the specified key.
The key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.
Examples
Basic usage:
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "a");
assert_eq!(map.contains_key(&1), true);
assert_eq!(map.contains_key(&2), false);Constructs a double-ended iterator over a sub-range of elements in the map.
The simplest way is to use the range syntax min..max, thus range(min..max) will
yield elements from min (inclusive) to max (exclusive).
The range may also be entered as (Bound<T>, Bound<T>), so for example
range((Excluded(4), Included(10))) will yield a left-exclusive, right-inclusive
range from 4 to 10.
Panics
Panics if range start > end.
Panics if range start == end and both bounds are Excluded.
Examples
Basic usage:
use std::collections::BTreeMap;
use std::ops::Bound::Included;
let mut map = BTreeMap::new();
map.insert(3, "a");
map.insert(5, "b");
map.insert(8, "c");
for (&key, &value) in map.range((Included(&4), Included(&8))) {
println!("{}: {}", key, value);
}
assert_eq!(Some((&5, &"b")), map.range(4..).next());Gets an iterator over the entries of the map, sorted by key.
Examples
Basic usage:
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(3, "c");
map.insert(2, "b");
map.insert(1, "a");
for (key, value) in map.iter() {
println!("{}: {}", key, value);
}
let (first_key, first_value) = map.iter().next().unwrap();
assert_eq!((*first_key, *first_value), (1, "a"));Gets an iterator over the keys of the map, in sorted order.
Examples
Basic usage:
use std::collections::BTreeMap;
let mut a = BTreeMap::new();
a.insert(2, "b");
a.insert(1, "a");
let keys: Vec<_> = a.keys().cloned().collect();
assert_eq!(keys, [1, 2]);Gets an iterator over the values of the map, in order by key.
Examples
Basic usage:
use std::collections::BTreeMap;
let mut a = BTreeMap::new();
a.insert(1, "hello");
a.insert(2, "goodbye");
let values: Vec<&str> = a.values().cloned().collect();
assert_eq!(values, ["hello", "goodbye"]);Returns the number of elements in the map.
Examples
Basic usage:
use std::collections::BTreeMap;
let mut a = BTreeMap::new();
assert_eq!(a.len(), 0);
a.insert(1, "a");
assert_eq!(a.len(), 1);