Enum SamplingStrategy 

pub enum SamplingStrategy {
    Full,
    Random {
        limit: usize,
    },
    ReservoirPK {
        sample_size: usize,
        pk: String,
    },
    TableSample {
        percentage: f32,
        limit: usize,
    },
}

Sampling strategy selection based on table size

Variants

Full

Full table scan - when sample_size >= row_count No randomization, deterministic results

Random

Random sampling for smaller tables (< 100k rows) Simple ORDER BY Random() LIMIT N

Fields

limit: usize

ReservoirPK

Reservoir sampling for medium tables (100K - 10M rows) uses primary key based random sampling for better performance

Fields

sample_size: usize

pk: String

TableSample

TABLESAMPLE for larger tables (> 10M rows) Postgresql’s built in sampling - fast and no table locks

Fields

percentage: f32

limit: usize

Implementations

impl SamplingStrategy

pub async fn auto_select( pool: &PgPool, schema: &str, table: &str, estimated_rows: Option<i64>, sample_size: usize, ) -> Result<Self, Error>

Auto select the best sampling strat based on table size

Strat selection

• < 100k rows: Random sampling
• 100k - 10M rows: Resevoir sampling with PK
• 10M rows: TABLESAMPLE

pub fn max_samples(&self) -> usize

Get the max number of samples that this strat should return

Trait Implementations

impl Clone for SamplingStrategy

fn clone(&self) -> SamplingStrategy

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SamplingStrategy

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

Formats the value using the given formatter.

impl PartialEq for SamplingStrategy

fn eq(&self, other: &SamplingStrategy) -> 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 StructuralPartialEq for SamplingStrategy