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[Internal] Parallel Hedging: Adds Docs #4082

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NaluTripician
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  • [] Bug fix (non-breaking change which fixes an issue)
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If you want to change the preferred regions for a `CosmosClient` you can do so by callinga new method.

```csharp
client.UpdatePreferredRegions(new List<string>() { "West US", "East US" });
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Making this mutable is risky - in Java we have instead allowed specifying excluded regions (and made that mutable) as well as configurable per request options. Achieves the same - but hasn't the same implications of making preferred regions mutable everywhere

```csharp
CosmosClientOptions options = new CosmosClientOptions()
{
SpeculativeProcessor = new ThresholdSpeculator(TimeSpan.FromMilliseconds(500))
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Is SpeculativeProcessor a public contract CX can add/extend?

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I think it might be better to have it be a private contract here. I will make it so it's only a private contract.

The example above will create a `CosmosClient` instance with speculative processing enabled with at 500ms threhshold. This means that if a request takes longer than 500ms the SDK will send a new request to the backend in order of the Preferred Regions List. This process will repeat until a request comes back. The SDK will then return the first response that comes back from the backend. The threshold parameter is a required parameter can can be set to any value greater than 0. There are also methods that will allow a user to disable/enabled speculative processing after the client has been created. If you include speculative processing when creating the client it will be enabled by default.

```csharp
client.DisableSpeculativeProcessing(); // Disables speculative processing
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Request level granular is also one ASK.
Assuming if we have that then are these APIs at Client scope still necessary?

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+1 requestOptions level override definitely is needed - especially for queries (but not just)

```csharp
RequestOptions requestOptions = new RequestOptions()
{
LocationToRouteTo = "West US"
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Will it be a single Region or Equivalent to PReferredRegions?

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Again - why do the opposite of Java (we used excluded regions here) - region to route to as an override owuld allow routing to a region which is not even in preferred regions?

I think it just opens a can of worms


```csharp
CosmosClient client = new CosmosClientBuilder("connection string")
.WithSpeculativeProcessing(type: SpeculationType.Threshold, speculativeThreshold: TimeSpan.FromMilliseconds(500))
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Remove Speculative/Speculation term everywhere

This has burned us already with Walmart - for customers "speculation" sounds too random. In Java we have used the term ThresholdBasedAvailabilityStartegy or something along those lines.

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Like here
WithAvailabilityStrategy(AvailabilityStartegyType.Threshold) or such

```csharp
CosmosClientOptions options = new CosmosClientOptions()
{
RegionConsistencyLevel = new ObservableCollection<string, ConsistencyLevel>()
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Wow - why is this needed?


This will override any logic the SDK does to determine where to route requests and will route the request to the region specified in the `LocationToRouteTo` property.

## Region Specific Conistency Levels
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I would be really curious why we would want to add this to public API ?

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As discussed - public API has too many inconsistencies with Java that have been discussed before and are pitfalls.

```csharp
RequestOptions requestOptions = new RequestOptions()
{
AvailabilityStrategyFallbackConsistencyLevel = ConsistencyLevel.Eventual
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This can be encapsulated by AvailabilityStrategyOptions as well right? Also, what are the consistency override semantics here - availability strategy level config overrides request level config overrides client level config?

@NaluTripician NaluTripician deleted the users/nalutripician/paralellHedgingApiDoc branch October 10, 2024 22:48
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4 participants