fix: sort condition in HistogramFold (#2674)

* sort ts before le

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>

* add test case

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>

---------

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>

src/promql/src/extension_plan/histogram_fold.rs

@@ -52,7 +52,7 @@ use futures::{ready, Stream, StreamExt};
 /// Due to the folding or sampling, the output rows number will become `input_rows` / `bucket_num`.
 ///
 /// # Requirement
-/// - Input should be sorted on `<tag list>, le ASC, ts`.
+/// - Input should be sorted on `<tag list>, ts, le ASC`.
 /// - The value set of `le` should be same. I.e., buckets of every series should be same.
 ///
 /// [1]: https://prometheus.io/docs/concepts/metric_types/#histogram
@@ -248,6 +248,14 @@ impl ExecutionPlan for HistogramFoldExec {
                 options: None,
             })
             .collect::<Vec<PhysicalSortRequirement>>();
+        // add ts
+        cols.push(PhysicalSortRequirement {
+            expr: Arc::new(PhyColumn::new(
+                self.input.schema().field(self.ts_column_index).name(),
+                self.ts_column_index,
+            )),
+            options: None,
+        });
         // add le ASC
         cols.push(PhysicalSortRequirement {
             expr: Arc::new(PhyCast::new(
@@ -263,14 +271,6 @@ impl ExecutionPlan for HistogramFoldExec {
                 nulls_first: false, // not nullable
             }),
         });
-        // add ts
-        cols.push(PhysicalSortRequirement {
-            expr: Arc::new(PhyColumn::new(
-                self.input.schema().field(self.ts_column_index).name(),
-                self.ts_column_index,
-            )),
-            options: None,
-        });
 
         vec![Some(cols)]
     }

tests/cases/standalone/common/promql/simple_histogram.result

@@ -244,3 +244,44 @@ drop table histogram2_bucket;
 
 Affected Rows: 0
 
+-- not from Prometheus
+-- makesure the sort expr works as expected
+create table histogram3_bucket (
+    ts timestamp time index,
+    le string,
+    s string,
+    val double,
+    primary key (s, le),
+);
+
+Affected Rows: 0
+
+insert into histogram3_bucket values
+    (2900000, "0.1", "a", 0),
+    (2900000, "1", "a", 0),
+    (2900000, "5", "a", 0),
+    (2900000, "+Inf", "a", 0),
+    (3000000, "0.1", "a", 50),
+    (3000000, "1", "a", 70),
+    (3000000, "5", "a", 110),
+    (3000000, "+Inf", "a", 120),
+    (3005000, "0.1", "a", 10),
+    (3005000, "1", "a", 20),
+    (3005000, "5", "a", 20),
+    (3005000, "+Inf", "a", 30);
+
+Affected Rows: 12
+
+tql eval (3000, 3005, '3s') histogram_quantile(0.5, sum by(le, s) (rate(histogram3_bucket[5m])));
+
++---+---------------------+---------------------------------+
+| s | ts                  | SUM(prom_rate(ts_range,val,ts)) |
++---+---------------------+---------------------------------+
+| a | 1970-01-01T00:50:00 | 0.55                            |
+| a | 1970-01-01T00:50:03 | 0.5500000000000002              |
++---+---------------------+---------------------------------+
+
+drop table histogram3_bucket;
+
+Affected Rows: 0
+

tests/cases/standalone/common/promql/simple_histogram.sql

@@ -132,3 +132,31 @@ tql eval (2820, 2820, '1s') histogram_quantile(0.5, rate(histogram2_bucket[15m])
 tql eval (2820, 2820, '1s') histogram_quantile(0.833, rate(histogram2_bucket[15m]));
 
 drop table histogram2_bucket;
+
+-- not from Prometheus
+-- makesure the sort expr works as expected
+create table histogram3_bucket (
+    ts timestamp time index,
+    le string,
+    s string,
+    val double,
+    primary key (s, le),
+);
+
+insert into histogram3_bucket values
+    (2900000, "0.1", "a", 0),
+    (2900000, "1", "a", 0),
+    (2900000, "5", "a", 0),
+    (2900000, "+Inf", "a", 0),
+    (3000000, "0.1", "a", 50),
+    (3000000, "1", "a", 70),
+    (3000000, "5", "a", 110),
+    (3000000, "+Inf", "a", 120),
+    (3005000, "0.1", "a", 10),
+    (3005000, "1", "a", 20),
+    (3005000, "5", "a", 20),
+    (3005000, "+Inf", "a", 30);
+
+tql eval (3000, 3005, '3s') histogram_quantile(0.5, sum by(le, s) (rate(histogram3_bucket[5m])));
+
+drop table histogram3_bucket;