Struct DictionaryBlock 

pub struct DictionaryBlock {
    pub dictionary: Vec<String>,
    pub encoded: Vec<(i64, u32)>,
}

A self-contained, serialisable dictionary-compressed block.

Fields

dictionary: Vec<String>

Reverse dictionary: dictionary[code] → string value.

encoded: Vec<(i64, u32)>

Encoded (timestamp_ms, code) pairs.

Implementations

impl DictionaryBlock

pub fn from_data(data: &[(i64, &str)]) -> TsdbResult<Self>

Build a block from a slice of (timestamp_ms, &str) pairs.

pub fn decode(&self) -> TsdbResult<Vec<(i64, &str)>>

Decode all (timestamp_ms, value_str) pairs.

pub fn decode_owned(&self) -> TsdbResult<Vec<(i64, String)>>

Decode all samples into owned String values.

pub fn lookup_code(&self, code: u32) -> Option<&str>

Look up the string for a given code.

Returns None if the code is out of range.

pub fn find_code(&self, value: &str) -> Option<u32>

Find the code assigned to value, or None if it is not in the dictionary.

pub fn get_value(&self, timestamp: i64) -> Option<&str>

Return the string value at the given timestamp_ms, or None if no sample exists at that exact timestamp.

pub fn cardinality(&self) -> usize

Number of distinct values in the dictionary.

pub fn len(&self) -> usize

Total number of encoded samples.

pub fn is_empty(&self) -> bool

Returns true if the block contains no samples.

pub fn compression_ratio(&self, avg_string_len: usize) -> f64

Approximate compression ratio vs. storing raw strings.

Assumes average string length of 10 bytes and 8-byte timestamp.

pub fn filter_range(&self, start: i64, end: i64) -> TsdbResult<Vec<(i64, &str)>>

Filter encoded samples to a timestamp range [start, end] (inclusive).

pub fn value_frequencies(&self) -> Vec<(&str, usize)>

Return the frequency of each distinct value as (value, count) pairs, sorted by count descending.

Trait Implementations

impl Clone for DictionaryBlock

fn clone(&self) -> DictionaryBlock

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DictionaryBlock

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for DictionaryBlock

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for DictionaryBlock

fn eq(&self, other: &DictionaryBlock) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for DictionaryBlock

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for DictionaryBlock