feat(subscription): add metrics for cursor (#18052)

grafana/risingwave-dev-dashboard.dashboard.py

@@ -1987,6 +1987,82 @@ def section_frontend(outer_panels):
                     ],
                     ["last"],
                 ),
+                panels.timeseries_count(
+                    "Subsription Cursor Nums",
+                    "The number of valid and invalid subscription cursor",
+                    [
+                        panels.target(
+                            f"{metric('subsription_cursor_nums')}",
+                            "",
+                        ),
+                        panels.target(
+                            f"{metric('invalid_subsription_cursor_nums')}",
+                            "",
+                        ),
+                    ],
+                ),
+                panels.timeseries_count(
+                    "Subscription Cursor Error Count",
+                    "The subscription error num of cursor",
+                    [
+                        panels.target(
+                            f"{metric('subscription_cursor_error_count')}",
+                            "",
+                        ),
+                    ],
+                ),
+                panels.timeseries_latency_ms(
+                    "Subscription Cursor Query Duration(ms)",
+                    "The amount of time a query exists inside the cursor",
+                    [
+                        *quantile(
+                            lambda quantile, legend: panels.target(
+                                f"histogram_quantile({quantile}, sum(rate({metric('subscription_cursor_query_duration_bucket')}[$__rate_interval])) by (le, subscription_name))",
+                                f"p{legend} - {{{{subscription_name}}}}",
+                            ),
+                            [50, 99, "max"],
+                        ),
+                    ],
+                ),
+                panels.timeseries_latency_ms(
+                    "Subscription Cursor Declare Duration(ms)",
+                    "Subscription cursor duration of declare",
+                    [
+                        *quantile(
+                            lambda quantile, legend: panels.target(
+                                f"histogram_quantile({quantile}, sum(rate({metric('subscription_cursor_declare_duration_bucket')}[$__rate_interval])) by (le, subscription_name))",
+                                f"p{legend} - {{{{subscription_name}}}}",
+                            ),
+                            [50, 99, "max"],
+                        )
+                    ],
+                ),
+                panels.timeseries_latency_ms(
+                    "Subscription Cursor Fetch Duration(ms)",
+                    "Subscription cursor duration of fetch",
+                    [
+                        *quantile(
+                            lambda quantile, legend: panels.target(
+                                f"histogram_quantile({quantile}, sum(rate({metric('subscription_cursor_fetch_duration_bucket')}[$__rate_interval])) by (le, subscription_name))",
+                                f"p{legend} - {{{{subscription_name}}}}",
+                            ),
+                            [50, 99, "max"],
+                        )
+                    ],
+                ),
+                panels.timeseries_latency_ms(
+                    "Subscription Cursor Last Fetch Duration(ms)",
+                    "Since the last fetch, the time up to now",
+                    [
+                        *quantile(
+                            lambda quantile, legend: panels.target(
+                                f"histogram_quantile({quantile}, sum(rate({metric('subscription_cursor_last_fetch_duration_bucket')}[$__rate_interval])) by (le, subscription_name))",
+                                f"p{legend} - {{{{subscription_name}}}}",
+                            ),
+                            [50, 99, "max"],
+                        )
+                    ],
+                ),
                 panels.timeseries_latency(
                     "Query Latency (Distributed Query Mode)",
                     "",

src/frontend/src/handler/declare_cursor.rs

@@ -82,7 +82,7 @@ async fn handle_declare_subscription_cursor(
         risingwave_sqlparser::ast::Since::Full => None,
     };
     // Create cursor based on the response
-    session
+    if let Err(e) = session
         .get_cursor_manager()
         .add_subscription_cursor(
             cursor_name.clone(),
@@ -91,7 +91,15 @@ async fn handle_declare_subscription_cursor(
             subscription,
             &handle_args,
         )
-        .await?;
+        .await
+    {
+        session
+            .env()
+            .cursor_metrics
+            .subscription_cursor_error_count
+            .inc();
+        return Err(e);
+    }
 
     Ok(PgResponse::empty_result(StatementType::DECLARE_CURSOR))
 }

src/frontend/src/monitor/stats.rs

@@ -12,16 +12,22 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use std::sync::LazyLock;
+use core::mem;
+use std::collections::HashMap;
+use std::sync::{Arc, LazyLock};
+use std::time::Duration;
 
-use prometheus::core::{AtomicU64, GenericCounter};
+use prometheus::core::{AtomicI64, AtomicU64, GenericCounter, GenericGauge};
 use prometheus::{
-    exponential_buckets, histogram_opts, register_histogram_with_registry,
-    register_int_counter_with_registry, register_int_gauge_with_registry, Histogram, IntGauge,
-    Registry,
+    exponential_buckets, histogram_opts, register_histogram_vec_with_registry,
+    register_histogram_with_registry, register_int_counter_with_registry,
+    register_int_gauge_with_registry, Histogram, HistogramVec, IntGauge, Registry,
 };
 use risingwave_common::metrics::TrAdderGauge;
 use risingwave_common::monitor::GLOBAL_METRICS_REGISTRY;
+use tokio::task::JoinHandle;
+
+use crate::session::SessionMapRef;
 
 #[derive(Clone)]
 pub struct FrontendMetrics {
@@ -80,3 +86,175 @@ impl FrontendMetrics {
         GLOBAL_FRONTEND_METRICS.clone()
     }
 }
+
+pub static GLOBAL_CURSOR_METRICS: LazyLock<CursorMetrics> =
+    LazyLock::new(|| CursorMetrics::new(&GLOBAL_METRICS_REGISTRY));
+
+#[derive(Clone)]
+pub struct CursorMetrics {
+    pub subscription_cursor_error_count: GenericCounter<AtomicU64>,
+    pub subscription_cursor_query_duration: HistogramVec,
+    pub subscription_cursor_declare_duration: HistogramVec,
+    pub subscription_cursor_fetch_duration: HistogramVec,
+    subsription_cursor_nums: GenericGauge<AtomicI64>,
+    invalid_subsription_cursor_nums: GenericGauge<AtomicI64>,
+    subscription_cursor_last_fetch_duration: HistogramVec,
+    _cursor_metrics_collector: Option<Arc<CursorMetricsCollector>>,
+}
+
+impl CursorMetrics {
+    pub fn new(registry: &Registry) -> Self {
+        let subscription_cursor_error_count = register_int_counter_with_registry!(
+            "subscription_cursor_error_count",
+            "The subscription error num of cursor",
+            registry
+        )
+        .unwrap();
+        let opts = histogram_opts!(
+            "subscription_cursor_query_duration",
+            "The amount of time a query exists inside the cursor",
+            exponential_buckets(1.0, 5.0, 11).unwrap(),
+        );
+        let subscription_cursor_query_duration =
+            register_histogram_vec_with_registry!(opts, &["subscription_name"], registry).unwrap();
+
+        let opts = histogram_opts!(
+            "subscription_cursor_declare_duration",
+            "Subscription cursor duration of declare",
+            exponential_buckets(1.0, 5.0, 11).unwrap(),
+        );
+        let subscription_cursor_declare_duration =
+            register_histogram_vec_with_registry!(opts, &["subscription_name"], registry).unwrap();
+
+        let opts = histogram_opts!(
+            "subscription_cursor_fetch_duration",
+            "Subscription cursor duration of fetch",
+            exponential_buckets(1.0, 5.0, 11).unwrap(),
+        );
+        let subscription_cursor_fetch_duration =
+            register_histogram_vec_with_registry!(opts, &["subscription_name"], registry).unwrap();
+
+        let subsription_cursor_nums = register_int_gauge_with_registry!(
+            "subsription_cursor_nums",
+            "The number of subscription cursor",
+            registry
+        )
+        .unwrap();
+        let invalid_subsription_cursor_nums = register_int_gauge_with_registry!(
+            "invalid_subsription_cursor_nums",
+            "The number of invalid subscription cursor",
+            registry
+        )
+        .unwrap();
+
+        let opts = histogram_opts!(
+            "subscription_cursor_last_fetch_duration",
+            "Since the last fetch, the time up to now",
+            exponential_buckets(1.0, 5.0, 11).unwrap(),
+        );
+        let subscription_cursor_last_fetch_duration =
+            register_histogram_vec_with_registry!(opts, &["subscription_name"], registry).unwrap();
+        Self {
+            _cursor_metrics_collector: None,
+            subscription_cursor_error_count,
+            subscription_cursor_query_duration,
+            subscription_cursor_declare_duration,
+            subscription_cursor_fetch_duration,
+            subsription_cursor_nums,
+            invalid_subsription_cursor_nums,
+            subscription_cursor_last_fetch_duration,
+        }
+    }
+
+    pub fn for_test() -> Self {
+        GLOBAL_CURSOR_METRICS.clone()
+    }
+
+    pub fn start_with_session_map(&mut self, session_map: SessionMapRef) {
+        self._cursor_metrics_collector = Some(Arc::new(CursorMetricsCollector::new(
+            session_map,
+            self.subsription_cursor_nums.clone(),
+            self.invalid_subsription_cursor_nums.clone(),
+            self.subscription_cursor_last_fetch_duration.clone(),
+        )));
+    }
+
+    pub fn init(session_map: SessionMapRef) -> Self {
+        let mut cursor_metrics = GLOBAL_CURSOR_METRICS.clone();
+        cursor_metrics.start_with_session_map(session_map);
+        cursor_metrics
+    }
+}
+
+pub struct PeriodicCursorMetrics {
+    pub subsription_cursor_nums: i64,
+    pub invalid_subsription_cursor_nums: i64,
+    pub subscription_cursor_last_fetch_duration: HashMap<String, f64>,
+}
+
+struct CursorMetricsCollector {
+    _join_handle: JoinHandle<()>,
+    shutdown_tx: Option<tokio::sync::oneshot::Sender<()>>,
+}
+impl CursorMetricsCollector {
+    fn new(
+        session_map: SessionMapRef,
+        subsription_cursor_nums: GenericGauge<AtomicI64>,
+        invalid_subsription_cursor_nums: GenericGauge<AtomicI64>,
+        subscription_cursor_last_fetch_duration: HistogramVec,
+    ) -> Self {
+        const COLLECT_INTERVAL_SECONDS: u64 = 60;
+
+        let (shutdown_tx, mut shutdown_rx) = tokio::sync::oneshot::channel();
+        let join_handle = tokio::spawn(async move {
+            let mut monitor_interval =
+                tokio::time::interval(Duration::from_secs(COLLECT_INTERVAL_SECONDS));
+            monitor_interval.set_missed_tick_behavior(tokio::time::MissedTickBehavior::Delay);
+            loop {
+                tokio::select! {
+                    // Wait for interval
+                    _ = monitor_interval.tick() => {},
+                    // Shutdown monitor
+                    _ = &mut shutdown_rx => {
+                        tracing::info!("Fragment info monitor is stopped");
+                        return;
+                    }
+                }
+
+                let session_vec = { session_map.read().values().cloned().collect::<Vec<_>>() };
+                let mut subsription_cursor_nums_value = 0;
+                let mut invalid_subsription_cursor_nums_value = 0;
+                for session in &session_vec {
+                    let periodic_cursor_metrics = session
+                        .get_cursor_manager()
+                        .get_periodic_cursor_metrics()
+                        .await;
+                    subsription_cursor_nums_value +=
+                        periodic_cursor_metrics.subsription_cursor_nums;
+                    invalid_subsription_cursor_nums_value +=
+                        periodic_cursor_metrics.invalid_subsription_cursor_nums;
+                    for (subscription_name, duration) in
+                        &periodic_cursor_metrics.subscription_cursor_last_fetch_duration
+                    {
+                        subscription_cursor_last_fetch_duration
+                            .with_label_values(&[subscription_name])
+                            .observe(*duration);
+                    }
+                }
+                subsription_cursor_nums.set(subsription_cursor_nums_value);
+                invalid_subsription_cursor_nums.set(invalid_subsription_cursor_nums_value);
+            }
+        });
+        Self {
+            _join_handle: join_handle,
+            shutdown_tx: Some(shutdown_tx),
+        }
+    }
+}
+impl Drop for CursorMetricsCollector {
+    fn drop(&mut self) {
+        if let Some(shutdown_tx) = mem::take(&mut self.shutdown_tx) {
+            shutdown_tx.send(()).ok();
+        }
+    }
+}