fix: align logical batcher example configuration expectations

Signed-off-by: WenyXu <wenymedia@gmail.com>

config/config.md

@@ -82,7 +82,7 @@
 | `pending_rows_batcher.worker_channel_capacity` | Integer | `65526` | Maximum queued submissions per table worker. |
 | `pending_rows_batcher.max_inflight_requests` | Integer | `3000` | Maximum admitted original requests awaiting completion. |
 | `pending_rows_batcher.flow_notification_queue_capacity` | Integer | `1024` | Maximum number of queued table Flow notifications. |
-| `pending_rows_batcher.logical_table` | -- | -- | Metric-engine logical-table batching for Prom remote write and non-legacy OTLP metrics.<br/>Requires prom_store.with_metric_engine. Logs, traces and legacy metrics are not eligible.<br/>These controls are independent and do not inherit the parent settings. |
+| `pending_rows_batcher.logical_table` | -- | -- | Metric-engine logical-table batching for Prom remote write and non-legacy OTLP metrics.<br/>Requires prom_store.with_metric_engine. Logs, traces and legacy metrics are not eligible.<br/>Enable independently with protocols and a nonzero flush interval.<br/>Omitted fields use independent defaults, not parent settings.<br/>Empty protocols or a zero interval disables logical batching without fallback.<br/>Omitting this entire section preserves legacy Prom batching; it does not enable OTLP batching. |
 | `pending_rows_batcher.logical_table.pending_rows_flush_interval` | String | `0s` | Flush interval measured from the first pending submission. Zero disables batching. |
 | `pending_rows_batcher.logical_table.max_batch_rows` | Integer | `100000` | Flush after a complete submission reaches this row threshold. |
 | `pending_rows_batcher.logical_table.max_concurrent_flushes` | Integer | `256` | Maximum concurrent flushes shared by Prom and OTLP metrics. |
@@ -350,7 +350,7 @@
 | `pending_rows_batcher.worker_channel_capacity` | Integer | `65526` | Maximum queued submissions per table worker. |
 | `pending_rows_batcher.max_inflight_requests` | Integer | `3000` | Maximum admitted original requests awaiting completion. |
 | `pending_rows_batcher.flow_notification_queue_capacity` | Integer | `1024` | Maximum number of queued table Flow notifications. |
-| `pending_rows_batcher.logical_table` | -- | -- | Metric-engine logical-table batching for Prom remote write and non-legacy OTLP metrics.<br/>Requires prom_store.with_metric_engine. Logs, traces and legacy metrics are not eligible.<br/>These controls are independent and do not inherit the parent settings. |
+| `pending_rows_batcher.logical_table` | -- | -- | Metric-engine logical-table batching for Prom remote write and non-legacy OTLP metrics.<br/>Requires prom_store.with_metric_engine. Logs, traces and legacy metrics are not eligible.<br/>Enable independently with protocols and a nonzero flush interval.<br/>Omitted fields use independent defaults, not parent settings.<br/>Empty protocols or a zero interval disables logical batching without fallback.<br/>Omitting this entire section preserves legacy Prom batching; it does not enable OTLP batching. |
 | `pending_rows_batcher.logical_table.pending_rows_flush_interval` | String | `0s` | Flush interval measured from the first pending submission. Zero disables batching. |
 | `pending_rows_batcher.logical_table.max_batch_rows` | Integer | `100000` | Flush after a complete submission reaches this row threshold. |
 | `pending_rows_batcher.logical_table.max_concurrent_flushes` | Integer | `256` | Maximum concurrent flushes shared by Prom and OTLP metrics. |

config/frontend.example.toml

@@ -263,7 +263,10 @@ flow_notification_queue_capacity = 1024
 
 ## Metric-engine logical-table batching for Prom remote write and non-legacy OTLP metrics.
 ## Requires prom_store.with_metric_engine. Logs, traces and legacy metrics are not eligible.
-## These controls are independent and do not inherit the parent settings.
+## Enable independently with protocols and a nonzero flush interval.
+## Omitted fields use independent defaults, not parent settings.
+## Empty protocols or a zero interval disables logical batching without fallback.
+## Omitting this entire section preserves legacy Prom batching; it does not enable OTLP batching.
 [pending_rows_batcher.logical_table]
 # protocols = ["prom", "otlp"]
 ## Flush interval measured from the first pending submission. Zero disables batching.

config/standalone.example.toml

@@ -242,7 +242,10 @@ flow_notification_queue_capacity = 1024
 
 ## Metric-engine logical-table batching for Prom remote write and non-legacy OTLP metrics.
 ## Requires prom_store.with_metric_engine. Logs, traces and legacy metrics are not eligible.
-## These controls are independent and do not inherit the parent settings.
+## Enable independently with protocols and a nonzero flush interval.
+## Omitted fields use independent defaults, not parent settings.
+## Empty protocols or a zero interval disables logical batching without fallback.
+## Omitting this entire section preserves legacy Prom batching; it does not enable OTLP batching.
 [pending_rows_batcher.logical_table]
 # protocols = ["prom", "otlp"]
 ## Flush interval measured from the first pending submission. Zero disables batching.

src/cmd/tests/load_config_test.rs

@@ -30,6 +30,7 @@ use datanode::config::{DatanodeOptions, RegionEngineConfig, StorageConfig};
 use file_engine::config::EngineConfig as FileEngineConfig;
 use flow::FlownodeOptions;
 use frontend::frontend::FrontendOptions;
+use frontend::service_config::PendingRowsBatcherOptions;
 use meta_client::MetaClientOptions;
 use meta_srv::metasrv::MetasrvOptions;
 use meta_srv::selector::SelectorType;
@@ -206,6 +207,10 @@ fn test_load_frontend_example_config() {
     );
     let expected = GreptimeOptions::<FrontendOptions> {
         component: FrontendOptions {
+            pending_rows_batcher: PendingRowsBatcherOptions {
+                logical_table: Some(Default::default()),
+                ..Default::default()
+            },
             default_timezone: Some("UTC".to_string()),
             default_column_prefix: Some("greptime".to_string()),
             auto_create_table: true,
@@ -389,6 +394,10 @@ fn test_load_standalone_example_config() {
     );
     let expected = GreptimeOptions::<StandaloneOptions> {
         component: StandaloneOptions {
+            pending_rows_batcher: PendingRowsBatcherOptions {
+                logical_table: Some(Default::default()),
+                ..Default::default()
+            },
             default_timezone: Some("UTC".to_string()),
             default_column_prefix: Some("greptime".to_string()),
             auto_create_table: true,