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PrefetchScanNode

  • Namespace: PPDS.Dataverse.Query.Planning.Nodes
  • Assembly: PPDS.Dataverse
  • Kind: Class
  • Implements: IQueryPlanNode

Summary​

Wraps any IQueryPlanNode to speculatively prefetch rows into a bounded buffer. The background producer fetches from the source node while the consumer reads ahead. Uses System.Threading.Channels for efficient producer-consumer with backpressure.

Members​

Constructors​

PrefetchScanNode(IQueryPlanNode source, int bufferSize)​

PrefetchScanNode(IQueryPlanNode source, int bufferSize)

Creates a prefetch wrapper around a source node.

  • Param source: The source node to prefetch from.

  • Param bufferSize: Maximum rows to buffer ahead (default: 5000 = ~3 FetchXML pages).

Methods​

ExecuteAsync​

IAsyncEnumerable<QueryRow> ExecuteAsync(QueryPlanContext context, CancellationToken cancellationToken)

Execute this node, producing rows.

Properties​

BufferSize​

int BufferSize { get; }

Number of rows to buffer ahead (controls memory usage).

Children​

IReadOnlyList<IQueryPlanNode> Children { get; }

Child nodes (inputs to this operator).

Description​

string Description { get; }

Human-readable description for EXPLAIN output.

EstimatedRows​

long EstimatedRows { get; }

Estimated row count (for cost-based decisions). -1 if unknown.

Source​

IQueryPlanNode Source { get; }

The source node to prefetch from.