Add log compaction docs

Author: kasun04

articles/event-hubs/TOC.yml

@@ -94,6 +94,8 @@
         href: event-hubs-capture-overview.md
       - name: Explore captured Avro files
         href: explore-captured-avro-files.md
+    - name: Log compaction
+      href: log-compaction.md
     - name: Application groups
       href: resource-governance-overview.md     
     - name: Tiers 
@@ -175,8 +177,6 @@
         href: event-hubs-amqp-troubleshoot.md
 - name: How-to guides
   items:
-    - name: Create and manage application groups
-      href: resource-governance-with-app-groups.md
     - name: Develop
       items:
         - name: Get Event Hubs connection string
@@ -203,6 +203,11 @@
               href: https://github.com/Azure/azure-sdk-for-python/blob/master/sdk/eventhub/azure-eventhub/README.md
             - name: JavaScript in GitHub (azure/event-hubs)
               href: https://github.com/Azure/azure-sdk-for-js/blob/master/sdk/eventhub/event-hubs/README.md
+    - name: Use log compaction
+      href: use-log-compaction.md
+    - name: Create and manage application groups
+      href: resource-governance-with-app-groups.md
+
     - name: Process data
       items:
         - name: Capture Event Hubs data in Parquet format

articles/event-hubs/event-hubs-features.md

@@ -33,7 +33,7 @@ Any entity that sends data to an event hub is an *event publisher* (synonymously
 
 You can publish an event via AMQP 1.0, the Kafka protocol, or HTTPS. The Event Hubs service provides [REST API](/rest/api/eventhub/) and [.NET](event-hubs-dotnet-standard-getstarted-send.md), [Java](event-hubs-java-get-started-send.md), [Python](event-hubs-python-get-started-send.md), [JavaScript](event-hubs-node-get-started-send.md), and [Go](event-hubs-go-get-started-send.md) client libraries for publishing events to an event hub. For other runtimes and platforms, you can use any AMQP 1.0 client, such as [Apache Qpid](https://qpid.apache.org/). 
 
-The choice to use AMQP or HTTPS is specific to the usage scenario. AMQP requires the establishment of a persistent bidirectional socket in addition to transport level security (TLS) or SSL/TLS. AMQP has higher network costs when initializing the session, however HTTPS requires additional TLS overhead for every request. AMQP has significantly higher performance for frequent publishers and can achieve much lower latencies when used with asynchronous publishing code.
+The choice to use AMQP or HTTPS is specific to the usage scenario. AMQP requires the establishment of a persistent bidirectional socket in addition to transport level security (TLS) or SSL/TLS. AMQP has higher network costs when initializing the session, however HTTPS requires extra TLS overhead for every request. AMQP has higher performance for frequent publishers and can achieve much lower latencies when used with asynchronous publishing code.
 
 You can publish events individually or batched. A single publication has a limit of 1 MB, regardless of whether it's a single event or a batch. Publishing events larger than this threshold will be rejected. 
 
@@ -163,6 +163,14 @@ If a reader disconnects from a partition, when it reconnects it begins reading a
 > - [JavaScript](https://github.com/Azure/azure-sdk-for-js/tree/main/sdk/eventhub/eventhubs-checkpointstore-blob/samples/v1/javascript) or  [TypeScript](https://github.com/Azure/azure-sdk-for-js/tree/main/sdk/eventhub/eventhubs-checkpointstore-blob/samples/v1/typescript)
 > - [Python](https://github.com/Azure/azure-sdk-for-python/blob/master/sdk/eventhub/azure-eventhub-checkpointstoreblob-aio/samples/)
 
+
+### Log compaction 
+
+Azure Event Hubs supports compacting event log to retain the latest events of a given event key. With compacted event hubs/Kafka topic, you can use key-baesd retention rather than using the coarser-grained time-based retention. 
+
+For more information on log compaction, see [Log compaction](log-compaction.md). 
+
+
 ### Common consumer tasks
 
 All Event Hubs consumers connect via an AMQP 1.0 session, a state-aware bidirectional communication channel. Each partition has an AMQP 1.0 session that facilitates the transport of events segregated by partition.

articles/event-hubs/event-hubs-for-kafka-ecosystem-overview.md

@@ -114,10 +114,6 @@ This feature is fundamentally at odds with Azure Event Hubs' multi-protocol mode
 
 The payload of any Event Hubs event is a byte stream and the content can be compressed with an algorithm of your choosing. The Apache Avro encoding format supports compression natively.
 
-### Log Compaction
-
-Apache Kafka log compaction is a feature that allows evicting all but the last record of each key from a partition, which effectively turns an Apache Kafka topic into a key-value store where the last value added overrides the previous one. This feature is presently not implemented by Azure Event Hubs. The key-value store pattern, even with frequent updates, is far better supported by database services like [Azure Cosmos DB](../cosmos-db/introduction.md). For more information, see [Log Projection](event-hubs-federation-overview.md#log-projections). 
-
 ### Kafka Streams
 
 Kafka Streams is a client library for stream analytics that is part of the Apache Kafka open-source project, but is separate from the Apache Kafka event stream broker.