c# - Signalr SQL 横向扩展 : drawbacks of using multiple streams?

Question

在SignalR Performance页面，我们可以阅读:

A Stream in this context is a scale unit used by the scaleout provider; this is a table if SQL Server is used, a Topic if Service Bus is used, and a Subscription if Redis is used. Each stream ensures ordered read and write operations; a single stream is a potential scale bottleneck, so the number of streams can be increased to help reduce that bottleneck. If multiple streams are used, SignalR will automatically distribute (shard) messages across these streams in a way that ensures messages sent from any given connection are in order.

流计数(即 SQL 中的表)可以这样设置:

var connectionString = "(your connection string)";
var config = new SqlScaleoutConfiguration(connectionString) { 
    TableCount = 3,
    MaxQueueLength = 50 };
GlobalHost.DependencyResolver.UseSqlServer(config);

但是 TableCount 在 SQL scaleout 中默认为 1。如果这是规模瓶颈，为什么默认为 1 ？如果我将它设置为 50 会怎么样？

文档没有提供任何线索来决定赋予哪个值。我应该将它设置为 1, 3, 10, 1000 吗？ 大值的优点和缺点是什么？它只会增加延迟吗？

Answer 1

来自文档:

https://msdn.microsoft.com/en-us/library/microsoft.aspnet.signalr.sqlscaleoutconfiguration(v=vs.118).aspx

TableCount
Gets or sets the number of tables to store messages in. Using more tables reduces lock contention and may increase throughput. This must be consistent between all nodes in the web farm. Defaults to 1.