From 301ffc1d911c349f9f9086bae45bbe7a985a0539 Mon Sep 17 00:00:00 2001
From: Weny Xu <wenymedia@gmail.com>
Date: Fri, 29 Dec 2023 16:46:48 +0900
Subject: [PATCH] feat(remote_wal): append a noop record after kafka topic
 initialization (#3040)

* feat: append a noop record after kafka topic initialization

* chore: apply suggestions from CR

* feat: ignore the noop record during the read
---
 src/common/meta/src/error.rs                  | 23 +++++++++
 .../meta/src/wal/kafka/topic_manager.rs       | 48 +++++++++++++++++--
 src/log-store/src/kafka/log_store.rs          |  4 ++
 3 files changed, 70 insertions(+), 5 deletions(-)

diff --git a/src/common/meta/src/error.rs b/src/common/meta/src/error.rs
index c120c8ba93..323d922b9c 100644
--- a/src/common/meta/src/error.rs
+++ b/src/common/meta/src/error.rs
@@ -321,6 +321,27 @@ pub enum Error {
         error: rskafka::client::error::Error,
     },
 
+    #[snafu(display(
+        "Failed to build a Kafka partition client, topic: {}, partition: {}",
+        topic,
+        partition
+    ))]
+    BuildKafkaPartitionClient {
+        topic: String,
+        partition: i32,
+        location: Location,
+        #[snafu(source)]
+        error: rskafka::client::error::Error,
+    },
+
+    #[snafu(display("Failed to produce records to Kafka, topic: {}", topic))]
+    ProduceRecord {
+        topic: String,
+        location: Location,
+        #[snafu(source)]
+        error: rskafka::client::error::Error,
+    },
+
     #[snafu(display("Failed to create a Kafka wal topic"))]
     CreateKafkaWalTopic {
         location: Location,
@@ -368,6 +389,8 @@ impl ErrorExt for Error {
             | EncodeWalOptions { .. }
             | BuildKafkaClient { .. }
             | BuildKafkaCtrlClient { .. }
+            | BuildKafkaPartitionClient { .. }
+            | ProduceRecord { .. }
             | CreateKafkaWalTopic { .. }
             | EmptyTopicPool { .. } => StatusCode::Unexpected,
 
diff --git a/src/common/meta/src/wal/kafka/topic_manager.rs b/src/common/meta/src/wal/kafka/topic_manager.rs
index 860192b970..80aaa90d40 100644
--- a/src/common/meta/src/wal/kafka/topic_manager.rs
+++ b/src/common/meta/src/wal/kafka/topic_manager.rs
@@ -21,13 +21,16 @@ use common_telemetry::{debug, error, info};
 use rskafka::client::controller::ControllerClient;
 use rskafka::client::error::Error as RsKafkaError;
 use rskafka::client::error::ProtocolError::TopicAlreadyExists;
-use rskafka::client::ClientBuilder;
+use rskafka::client::partition::{Compression, UnknownTopicHandling};
+use rskafka::client::{Client, ClientBuilder};
+use rskafka::record::Record;
 use rskafka::BackoffConfig;
 use snafu::{ensure, AsErrorSource, ResultExt};
 
 use crate::error::{
-    BuildKafkaClientSnafu, BuildKafkaCtrlClientSnafu, CreateKafkaWalTopicSnafu, DecodeJsonSnafu,
-    EncodeJsonSnafu, InvalidNumTopicsSnafu, Result,
+    BuildKafkaClientSnafu, BuildKafkaCtrlClientSnafu, BuildKafkaPartitionClientSnafu,
+    CreateKafkaWalTopicSnafu, DecodeJsonSnafu, EncodeJsonSnafu, InvalidNumTopicsSnafu,
+    ProduceRecordSnafu, Result,
 };
 use crate::kv_backend::KvBackendRef;
 use crate::rpc::store::PutRequest;
@@ -37,6 +40,10 @@ use crate::wal::kafka::KafkaConfig;
 
 const CREATED_TOPICS_KEY: &str = "__created_wal_topics/kafka/";
 
+// Each topic only has one partition for now.
+// The `DEFAULT_PARTITION` refers to the index of the partition.
+const DEFAULT_PARTITION: i32 = 0;
+
 /// Manages topic initialization and selection.
 pub struct TopicManager {
     config: KafkaConfig,
@@ -117,14 +124,20 @@ impl TopicManager {
             .await
             .with_context(|_| BuildKafkaClientSnafu {
                 broker_endpoints: self.config.broker_endpoints.clone(),
-            })?
+            })?;
+
+        let control_client = client
             .controller_client()
             .context(BuildKafkaCtrlClientSnafu)?;
 
         // Try to create missing topics.
         let tasks = to_be_created
             .iter()
-            .map(|i| self.try_create_topic(&topics[*i], &client))
+            .map(|i| async {
+                self.try_create_topic(&topics[*i], &control_client).await?;
+                self.try_append_noop_record(&topics[*i], &client).await?;
+                Ok(())
+            })
             .collect::<Vec<_>>();
         futures::future::try_join_all(tasks).await.map(|_| ())
     }
@@ -141,6 +154,31 @@ impl TopicManager {
             .collect()
     }
 
+    async fn try_append_noop_record(&self, topic: &Topic, client: &Client) -> Result<()> {
+        let partition_client = client
+            .partition_client(topic, DEFAULT_PARTITION, UnknownTopicHandling::Retry)
+            .await
+            .context(BuildKafkaPartitionClientSnafu {
+                topic,
+                partition: DEFAULT_PARTITION,
+            })?;
+
+        partition_client
+            .produce(
+                vec![Record {
+                    key: None,
+                    value: None,
+                    timestamp: rskafka::chrono::Utc::now(),
+                    headers: Default::default(),
+                }],
+                Compression::NoCompression,
+            )
+            .await
+            .context(ProduceRecordSnafu { topic })?;
+
+        Ok(())
+    }
+
     async fn try_create_topic(&self, topic: &Topic, client: &ControllerClient) -> Result<()> {
         match client
             .create_topic(
diff --git a/src/log-store/src/kafka/log_store.rs b/src/log-store/src/kafka/log_store.rs
index 73b0fe1de2..df64fa6657 100644
--- a/src/log-store/src/kafka/log_store.rs
+++ b/src/log-store/src/kafka/log_store.rs
@@ -186,6 +186,10 @@ impl LogStore for KafkaLogStore {
                     record_offset, ns_clone, high_watermark
                 );
 
+                // Ignores the noop record.
+                if record.record.value.is_none() {
+                    continue;
+                }
                 let entries = decode_from_record(record.record)?;
 
                 // Filters entries by region id.