deephaven.concurrency_control

This module defines the Barrier marker class and the ConcurrencyControl generic protocol that can be subclassed and implemented by Selectable and Filter to provide explicit concurrency control during evaluation of the select, update, and where table operations.

See https://deephaven.io/core/docs/conceptual/query-engine/parallelization/ for more details on concurrency control.

class Barrier

Bases: JObjectWrapper

A hollow marker class representing a barrier. A barrier imposes an ordering constraint for the filters or selectables that respect the same barrier. When a filter/selectable is marked as respecting a barrier object, it indicates that the respecting filter/selectable will be executed entirely after the filter/selectable declaring the barrier.

j_object_type

alias of Object

class ConcurrencyControl(*args, **kwargs)

Bases: Protocol[T]

An abstract class representing concurrency control features for Selectable and Filter.

abstract with_declared_barriers(barriers)

Returns a new instance with the given declared barriers.

Return type:

TypeVar(T)

abstract with_respected_barriers(barriers)

Returns a new instance with the given respected barriers.

Return type:

TypeVar(T)

abstract with_serial()

Returns a new instance with column-wise serial evaluation enforced, i.e. rows in the column are guaranteed to evaluated in order.

Return type:

TypeVar(T)