ParallelMergeOptions Enumeration

Task Parallel System.Threading

Specifies the preferred type of output merge to use in a query. This is a hint only, and may not be respected by the system when parallelizing all queries.

Namespace:  System.Linq
Assembly:  System.Threading (in System.Threading.dll)

Syntax

Visual Basic (Declaration)
Public Enumeration ParallelMergeOptions
C#
public enum ParallelMergeOptions

Members

Member nameDescription
Default
Use the default merge type, which is AutoBuffered.
NotBuffered
Use a merge without output buffers. As soon as result elements have been computed, make that element available to the consumer of the query.
AutoBuffered
Use a merge with output buffers of a size chosen by the system. Results will accumulate into an output buffer before they are available to the consumer of the query.
FullyBuffered
Use a merge with full output buffers. The system will accumulate all of the results before making any of them available to the consumer of the query.

Remarks

Use NotBuffered for queries that will be consumed and output as streams, this has the lowest latency between beginning query execution and elements being yielded. For some queries, such as those involving a sort (OrderBy, OrderByDescending), buffering is essential and a hint of NotBuffered or AutoBuffered will be ignored.

Use AutoBuffered for most cases; this is the default. It strikes a balance between latency and overall performance.

Use FullyBuffered for queries when the entire output can be processed before the information is needed. This option offers the best performance when all of the output can be accumulated before yielding any information, though it is not suitable for stream processing or showing partial results mid-query.

See Also