Package io.deephaven.extensions.barrage

Class ColumnEncoding

java.lang.Object

io.deephaven.extensions.barrage.ColumnEncoding

public final class ColumnEncoding
extends Object

Arrow encoding to apply to a column when generating a Barrage schema. Auto-detected per column by BarrageUtil.schemaFromTable(io.deephaven.engine.table.Table) when structural guarantees make a particular encoding clearly beneficial, or specified explicitly via Table.BARRAGE_SCHEMA_ATTRIBUTE.

An encoding carries two independent facets: an optional run-end encoding (REE) run_ends index width, and an optional dictionary-index width. When both are present the column is doubly-encoded as RunEndEncoded<Dictionary<...>> -- REE collapses runs on the row axis and the dictionary dedupes the per-run values. The historical single-facet constants (RUN_END_ENCODED_INT32, DICTIONARY_ENCODED_INT32, ...) remain available as canonical singletons; compose them with withDictionary(io.deephaven.extensions.barrage.ColumnEncoding.DictWidth) / withRunEnd(io.deephaven.extensions.barrage.ColumnEncoding.RunEndWidth).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	ColumnEncoding.DictWidth	Width of the dictionary index (the values shipped in the RecordBatch).
static enum	ColumnEncoding.RunEndWidth	Width of the REE run_ends index child.

Field Summary

Fields

Modifier and Type	Field	Description
static final ColumnEncoding	DICTIONARY_ENCODED_INT16
static final ColumnEncoding	DICTIONARY_ENCODED_INT32
static final ColumnEncoding	DICTIONARY_ENCODED_INT64
static final ColumnEncoding	DICTIONARY_ENCODED_INT8
static final ColumnEncoding	RUN_END_ENCODED_INT16
static final ColumnEncoding	RUN_END_ENCODED_INT32
static final ColumnEncoding	RUN_END_ENCODED_INT64

Method Summary

Modifier and Type	Method	Description
ColumnEncoding.DictWidth	dictWidth()	The dictionary index width, or null if not dictionary encoded.
boolean	equals(Object o)
int	hashCode()
boolean	isDictionaryEncoded()	Returns true if this encoding includes dictionary encoding.
boolean	isRunEndEncoded()	Returns true if this encoding includes run-end encoding.
static ColumnEncoding	of(ColumnEncoding.RunEndWidth runEndWidth, ColumnEncoding.DictWidth dictWidth)	Returns an encoding with the given (possibly null) facets.
ColumnEncoding.RunEndWidth	runEndWidth()	The REE run_ends width, or null if not run-end encoded.
String	toString()
ColumnEncoding	withDictionary(ColumnEncoding.DictWidth width)	Returns a copy of this encoding with dictionary encoding added (or its width replaced).
ColumnEncoding	withRunEnd(ColumnEncoding.RunEndWidth width)	Returns a copy of this encoding with run-end encoding added (or its width replaced).

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Details

RUN_END_ENCODED_INT16

public static final ColumnEncoding RUN_END_ENCODED_INT16

RUN_END_ENCODED_INT32

public static final ColumnEncoding RUN_END_ENCODED_INT32

RUN_END_ENCODED_INT64

public static final ColumnEncoding RUN_END_ENCODED_INT64

DICTIONARY_ENCODED_INT8

public static final ColumnEncoding DICTIONARY_ENCODED_INT8

DICTIONARY_ENCODED_INT16

public static final ColumnEncoding DICTIONARY_ENCODED_INT16

DICTIONARY_ENCODED_INT32

public static final ColumnEncoding DICTIONARY_ENCODED_INT32

DICTIONARY_ENCODED_INT64

public static final ColumnEncoding DICTIONARY_ENCODED_INT64

Method Details

of

public static ColumnEncoding of(ColumnEncoding.RunEndWidth runEndWidth,
 ColumnEncoding.DictWidth dictWidth)

Returns an encoding with the given (possibly null) facets. Prefer the named singletons and withDictionary(io.deephaven.extensions.barrage.ColumnEncoding.DictWidth) / withRunEnd(io.deephaven.extensions.barrage.ColumnEncoding.RunEndWidth) for readability.

withDictionary

public ColumnEncoding withDictionary(ColumnEncoding.DictWidth width)

Returns a copy of this encoding with dictionary encoding added (or its width replaced).

withRunEnd

public ColumnEncoding withRunEnd(ColumnEncoding.RunEndWidth width)

Returns a copy of this encoding with run-end encoding added (or its width replaced).

isRunEndEncoded

public boolean isRunEndEncoded()

Returns true if this encoding includes run-end encoding.

isDictionaryEncoded

public boolean isDictionaryEncoded()

Returns true if this encoding includes dictionary encoding.

runEndWidth

public ColumnEncoding.RunEndWidth runEndWidth()

The REE run_ends width, or null if not run-end encoded.

dictWidth

public ColumnEncoding.DictWidth dictWidth()

The dictionary index width, or null if not dictionary encoded.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object