[Doc] Add doc for init sub config in DLQ policy and producer (apache#…

…13995)
rkaw92 · Feb 14, 2022 · 6d79fcc · 6d79fcc
1 parent 7ab2987
commit 6d79fcc
Show file tree

Hide file tree

Showing 2 changed files with 17 additions and 0 deletions.
diff --git a/site2/docs/client-libraries-java.md b/site2/docs/client-libraries-java.md
@@ -209,6 +209,7 @@ Name| Type |  <div style="width:300px">Description</div>|  Default
 `batchingEnabled`| boolean|Enable batching of messages. |true
 `chunkingEnabled` | boolean | Enable chunking of messages. |false
 `compressionType`|CompressionType|Message data compression type used by a producer. <br />Available options:<li>[`LZ4`](https://github.com/lz4/lz4)</li><li>[`ZLIB`](https://zlib.net/)<br /><li>[`ZSTD`](https://facebook.github.io/zstd/)</li><li>[`SNAPPY`](https://google.github.io/snappy/)</li>| No compression
+`initialSubscriptionName`|string|Use this configuration to automatically create an initial subscription when creating a topic. If this field is not set, the initial subscription is not created.|null
 
 You can configure parameters if you do not want to use the default configuration.
 

diff --git a/site2/docs/concepts-messaging.md b/site2/docs/concepts-messaging.md
@@ -317,6 +317,22 @@ Consumer<byte[]> consumer = pulsarClient.newConsumer(Schema.BYTES)
                 
 ```
 
+By default, there is no subscription during a DLQ topic creation. Without a just-in-time subscription to the DLQ topic, you may lose messages. To automatically create an initial subscription for the DLQ, you can specify the `initialSubscriptionName` parameter.
+
+```java
+Consumer<byte[]> consumer = pulsarClient.newConsumer(Schema.BYTES)
+                .topic(topic)
+                .subscriptionName("my-subscription")
+                .subscriptionType(SubscriptionType.Shared)
+                .deadLetterPolicy(DeadLetterPolicy.builder()
+                      .maxRedeliverCount(maxRedeliveryCount)
+                      .deadLetterTopic("your-topic-name")
+                      .initialSubscriptionName("init-sub")
+                      .build())
+                .subscribe();
+                
+```
+
 Dead letter topic depends on message redelivery. Messages are redelivered either due to [acknowledgement timeout](#acknowledgement-timeout) or [negative acknowledgement](#negative-acknowledgement). If you are going to use negative acknowledgement on a message, make sure it is negatively acknowledged before the acknowledgement timeout. 
 
 > **Note**