graph: Add a facility for tracking query effort

Author: lutter

graph/src/data/graphql/effort.rs

@@ -0,0 +1,55 @@
+//! Utilities to keep moving statistics about queries
+
+use std::collections::HashMap;
+use std::sync::{Arc, RwLock};
+use std::time::{Duration, Instant};
+
+use crate::util::stats::MovingStats;
+
+pub struct QueryEffort {
+    inner: Arc<RwLock<QueryEffortInner>>,
+}
+
+/// Track the effort for queries (identified by their ShapeHash) over a
+/// time window.
+struct QueryEffortInner {
+    window_size: Duration,
+    bin_size: Duration,
+    effort: HashMap<u64, MovingStats>,
+    total: MovingStats,
+}
+
+impl QueryEffort {
+    pub fn new(window_size: Duration, bin_size: Duration) -> Self {
+        Self {
+            inner: Arc::new(RwLock::new(QueryEffortInner::new(window_size, bin_size))),
+        }
+    }
+
+    pub fn add(&self, shape_hash: u64, duration: Duration) {
+        let mut inner = self.inner.write().unwrap();
+        inner.add(shape_hash, duration);
+    }
+}
+
+impl QueryEffortInner {
+    fn new(window_size: Duration, bin_size: Duration) -> Self {
+        Self {
+            window_size,
+            bin_size,
+            effort: HashMap::default(),
+            total: MovingStats::new(window_size, bin_size),
+        }
+    }
+
+    fn add(&mut self, shape_hash: u64, duration: Duration) {
+        let window_size = self.window_size;
+        let bin_size = self.bin_size;
+        let now = Instant::now();
+        self.effort
+            .entry(shape_hash)
+            .or_insert_with(|| MovingStats::new(window_size, bin_size))
+            .add_at(now, duration);
+        self.total.add_at(now, duration);
+    }
+}

graph/src/data/graphql/mod.rs

@@ -21,3 +21,5 @@ pub use self::values::{
 };
 
 pub mod shape_hash;
+
+pub mod effort;

graph/src/lib.rs

@@ -151,4 +151,5 @@ pub mod prelude {
     pub use crate::log::split::split_logger;
     pub use crate::util::error::CompatErr;
     pub use crate::util::futures::{retry, TimeoutError};
+    pub use crate::util::stats::MovingStats;
 }