Update Kafka operator docs for batching and NDJSON defaults

src/content/docs/integrations/kafka.mdx

@@ -44,4 +44,4 @@ to_kafka "topic"
 
 You can control the message encoding with the `message` argument in
 [`to_kafka`](/reference/operators/to_kafka) that defaults to
-`this.print_json()`.
+`this.print_ndjson()`.

src/content/docs/reference/operators/from_kafka.mdx

@@ -12,7 +12,7 @@ Receives events from an Apache Kafka topic.
 
 ```tql
 from_kafka topic:string, [count=int, exit=bool, offset=int|string, options=record,
-           aws_iam=record, aws_region=string, commit_batch_size=int]
+           aws_iam=record, aws_region=string, batch_size=int, batch_timeout=duration]
 ```
 
 ## Description
@@ -84,14 +84,21 @@ options][librdkafka-options] to configure Kafka according to your needs.
 We recommend factoring these options into the plugin-specific `kafka.yaml` so
 that they are independent of the `from_kafka` arguments.
 
-### `commit_batch_size = int (optional)`
+### `batch_size = int (optional)`
 
-The operator commits offsets after receiving `commit_batch_size` messages
-to improve throughput. If you need to ensure exactly-once semantics for your
-pipeline, set this option to `1` to commit every message individually.
+The number of messages to accumulate before emitting a batch. The operator
+commits offsets after each batch to improve throughput.
 
 Defaults to `1000`.
 
+### `batch_timeout = duration (optional)`
+
+The maximum time to wait before flushing a partial batch. If the operator
+receives fewer than `batch_size` messages within this interval, it emits
+and commits whatever it has collected so far.
+
+Defaults to `10s`.
+
 ## Amazon MSK
 
 The operator supports [Amazon MSK](/integrations/amazon/msk) with IAM

src/content/docs/reference/operators/to_kafka.mdx

@@ -1,7 +1,7 @@
 ---
 title: to_kafka
 category: Outputs/Events
-example: 'to_kafka "topic", message=this.print_json()'
+example: 'to_kafka "topic", message=this.print_ndjson()'
 ---
 
 import Op from '@components/see-also/Op.astro';
@@ -41,7 +41,7 @@ The Kafka topic to send messages to.
 
 An expression that evaluates to the message content for each row.
 
-Defaults to `this.print_json()` when not specified.
+Defaults to `this.print_ndjson()` when not specified.
 
 ### `key = string (optional)`
 
@@ -72,7 +72,7 @@ connecting to MSK with IAM authentication.
 
 ## Examples
 
-### Send JSON-formatted events to topic `events` (using default)
+### Send NDJSON-formatted events to topic `events` (using default)
 
 Stream security events to a Kafka topic with automatic JSON formatting:
 
@@ -85,7 +85,8 @@ to_kafka "events"
 
 This pipeline subscribes to security alerts, filters for high-severity events,
 selects relevant fields, and sends them to Kafka as JSON. Each event is
-automatically formatted using `this.print_json()`, producing messages like:
+automatically formatted using `this.print_ndjson()`, producing one NDJSON line per
+event:
 
 ```json
 {
@@ -96,11 +97,11 @@ automatically formatted using `this.print_json()`, producing messages like:
 }
 ```
 
-### Send JSON-formatted events with explicit message
+### Send NDJSON-formatted events with explicit message
 
 ```tql
 subscribe "logs"
-to_kafka "events", message=this.print_json()
+to_kafka "events", message=this.print_ndjson()
 ```
 
 ### Send specific field values with a timestamp
@@ -114,7 +115,7 @@ to_kafka "alerts", message=alert_msg, timestamp=2024-01-01T00:00:00
 
 ```tql
 metrics
-to_kafka "metrics", message=this.print_json(), key="server-01"
+to_kafka "metrics", message=this.print_ndjson(), key="server-01"
 ```
 
 ## See Also