Class ContinuousQueryOptions

Namespace

Apache.Ignite.Table

Assembly

Apache.Ignite.dll

Continuous query options.

public sealed record ContinuousQueryOptions : IEquatable<ContinuousQueryOptions>

Inheritance

object

ContinuousQueryOptions

Implements

IEquatable<ContinuousQueryOptions>

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Constructors

ContinuousQueryOptions()

Initializes a new instance of the ContinuousQueryOptions class.

public ContinuousQueryOptions()

ContinuousQueryOptions(IContinuousQueryWatermark?, ICollection<string>?, ICollection<TableRowEventType>?, int, TimeSpan, bool)

Continuous query options.

public ContinuousQueryOptions(IContinuousQueryWatermark? Watermark, ICollection<string>? ColumnNames, ICollection<TableRowEventType>? EventTypes, int PageSize, TimeSpan PollInterval, bool EnableEmptyBatches = false)

Parameters

Watermark IContinuousQueryWatermark

Starting watermark. When null, the query will start from the current time. Watermark can be obtained from physical time (FromInstant(Instant)) or from a previous event (GetWatermark()).

The default value is null, meaning the query will start from the current time.

ColumnNames ICollection<string>

Column names to include. When null, all columns are included.

By default, all columns are included.

EventTypes ICollection<TableRowEventType>

Event types to include. When null, all event types are included.

By default, all event types are included.

PageSize int

Per-partition page size.

Continuous Query polls every partition in a loop. This parameter controls the number of entries that will be requested from a single partition in one network call. Therefore, the maximum number of entries that the query may hold in memory at any given time is pageSize * partitions.

The default value is DefaultPageSize.

PollInterval TimeSpan

Poll interval.

The default value is DefaultPollInterval.

EnableEmptyBatches bool

When true, empty batches are returned when there are no new events to track watermark updates.

The default value is false, meaning that empty batches are not returned.

Fields

Default

Default continuous query options.

public static readonly ContinuousQueryOptions Default

Field Value

ContinuousQueryOptions

DefaultLongPollingWaitTime

Default long polling wait time (10 seconds).

public static readonly TimeSpan DefaultLongPollingWaitTime

Field Value

TimeSpan

DefaultPageSize

Default page size (1000).

public const int DefaultPageSize = 1000

Field Value

int

DefaultPollInterval

Default poll interval (1 second).

public static readonly TimeSpan DefaultPollInterval

Field Value

TimeSpan

Properties

ColumnNames

Column names to include. When null, all columns are included.

By default, all columns are included.

public ICollection<string>? ColumnNames { get; init; }

Property Value

ICollection<string>

EnableEmptyBatches

When true, empty batches are returned when there are no new events to track watermark updates.

The default value is false, meaning that empty batches are not returned.

public bool EnableEmptyBatches { get; init; }

Property Value

bool

EventTypes

Event types to include. When null, all event types are included.

By default, all event types are included.

public ICollection<TableRowEventType>? EventTypes { get; init; }

Property Value

ICollection<TableRowEventType>

LongPollingWaitTime

Gets the long polling wait time. A zero or negative value disables long polling.

Long polling is an optimization that reduces latency and network round trips. When the client polls a partition and no events are immediately available, instead of returning an empty response, the server holds the request open for up to LongPollingWaitTime, waiting for new events to arrive. If events arrive during this wait period, they are returned immediately. If the timeout expires with no events, an empty response is returned.

Works together with PollInterval. After receiving a response (with or without data), the client waits for PollInterval. For minimal latency, reduce PollInterval and increase LongPollingWaitTime. For better throughput and batching, increase PollInterval and PageSize.

The default value is DefaultLongPollingWaitTime.

public TimeSpan LongPollingWaitTime { get; init; }

Property Value

TimeSpan

PageSize

Per-partition page size.

Continuous Query polls every partition in a loop. This parameter controls the number of entries that will be requested from a single partition in one network call. Therefore, the maximum number of entries that the query may hold in memory at any given time is pageSize * partitions.

The default value is DefaultPageSize.

public int PageSize { get; init; }

Property Value

int

PollInterval

Poll interval.

The default value is DefaultPollInterval.

public TimeSpan PollInterval { get; init; }

Property Value

TimeSpan

Watermark

Starting watermark. When null, the query will start from the current time. Watermark can be obtained from physical time (FromInstant(Instant)) or from a previous event (GetWatermark()).

The default value is null, meaning the query will start from the current time.

public IContinuousQueryWatermark? Watermark { get; init; }

Property Value

IContinuousQueryWatermark