duckdb::ReservoirSamplePercentage Class Reference

The reservoir sample sample_size class maintains a streaming sample of variable size. More...

Inheritance diagram for duckdb::ReservoirSamplePercentage:

Collaboration diagram for duckdb::ReservoirSamplePercentage:

Public Member Functions
	ReservoirSamplePercentage (Allocator &allocator, double percentage, int64_t seed=-1)
	ReservoirSamplePercentage (double percentage, int64_t seed, idx_t reservoir_sample_size)
	ReservoirSamplePercentage (double percentage, int64_t seed=-1)
void	AddToReservoir (DataChunk &input) override
	Add a chunk of data to the sample.
unique_ptr< BlockingSample >	Copy () const override
unique_ptr< DataChunk >	GetChunk () override
	Fetches a chunk from the sample. If destory = true this method is descructive.
void	Finalize () override
void	Serialize (Serializer &serializer) const override
Public Member Functions inherited from duckdb::BlockingSample
	BlockingSample (int64_t seed=-1)
virtual void	Destroy ()
std::pair< double, idx_t >	PopFromWeightQueue ()
	Helper functions needed to merge two reservoirs while respecting weights of sampled rows.
double	GetMinWeightThreshold ()
idx_t	GetPriorityQueueSize ()
template<class TARGET >
TARGET &	Cast ()
template<class TARGET >
const TARGET &	Cast () const

Static Public Member Functions
static unique_ptr< BlockingSample >	Deserialize (Deserializer &deserializer)
Static Public Member Functions inherited from duckdb::BlockingSample
static unique_ptr< BlockingSample >	Deserialize (Deserializer &deserializer)

Static Public Attributes
static constexpr const SampleType	TYPE = SampleType::RESERVOIR_PERCENTAGE_SAMPLE
Static Public Attributes inherited from duckdb::BlockingSample
static constexpr const SampleType	TYPE = SampleType::BLOCKING_SAMPLE

Private Attributes
Allocator &	allocator
double	sample_percentage
	The sample_size to sample.
idx_t	reservoir_sample_size
	The fixed sample size of the sub-reservoirs.
unique_ptr< ReservoirSample >	current_sample
	The current sample.
vector< unique_ptr< ReservoirSample > >	finished_samples
	The set of finished samples of the reservoir sample.
idx_t	current_count = 0
	The amount of tuples that have been processed so far (not put in the reservoir, just processed)
bool	is_finalized

Static Private Attributes
static constexpr idx_t	RESERVOIR_THRESHOLD = 100000

Additional Inherited Members
Public Attributes inherited from duckdb::BlockingSample
unique_ptr< BaseReservoirSampling >	base_reservoir_sample
SampleType	type
	The sample type.
bool	destroyed
	has the sample been destroyed due to updates to the referenced table

Detailed Description

The reservoir sample sample_size class maintains a streaming sample of variable size.

Member Function Documentation

AddToReservoir()

void duckdb::ReservoirSamplePercentage::AddToReservoir ( DataChunk &  input )

overridevirtual

Add a chunk of data to the sample.

Implements duckdb::BlockingSample.

Copy()

unique_ptr< BlockingSample > duckdb::ReservoirSamplePercentage::Copy ( ) const

overridevirtual

Implements duckdb::BlockingSample.

GetChunk()

unique_ptr< DataChunk > duckdb::ReservoirSamplePercentage::GetChunk ( )

overridevirtual

Fetches a chunk from the sample. If destory = true this method is descructive.

Implements duckdb::BlockingSample.

Finalize()

void duckdb::ReservoirSamplePercentage::Finalize ( )

overridevirtual

Implements duckdb::BlockingSample.

Serialize()

void duckdb::ReservoirSamplePercentage::Serialize ( Serializer &  serializer ) const

overridevirtual

Reimplemented from duckdb::BlockingSample.

Member Data Documentation

is_finalized

bool duckdb::ReservoirSamplePercentage::is_finalized

private

Whether or not the stream is finalized. The stream is automatically finalized on the first call to GetChunkAndShrink();

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The documentation for this class was generated from the following file:

• external/duckdb/duckdb.hpp