ESQL: Implement MIN and MAX agg for exponential histograms

x-pack/plugin/esql/qa/testFixtures/src/main/resources/exponential_histogram.csv-spec

@@ -14,6 +14,73 @@ dummy-zero_count_only     | "{""scale"":2,""sum"":0.0,""min"":0.0,""max"":0.0,""
 dummy-zero_threshold_only | "{""scale"":0,""sum"":0.0,""zero"":{""threshold"":2.0E-5}}"
 ;
 
+
+
+allAggsGrouped
+required_capability: exponential_histogram_minmax_support
+
+FROM exp_histo_sample 
+ | EVAL instance = CASE(STARTS_WITH(instance, "dummy"), "dummy-grouped", instance)
+ | STATS min = MIN(responseTime), max = MAX(responseTime), p75 = PERCENTILE(responseTime,75) BY instance
+ | EVAL p75 = ROUND(p75, 7) // rounding to avoid floating point precision issues
+ | KEEP instance, min, max, p75
+ | SORT instance
+;
+
+instance:keyword | min:double | max:double | p75:double
+dummy-grouped    | -100.0     | 50.0       | 8.3457089
+instance-0       | 2.4E-4     | 6.786232   | 0.2608237
+instance-1       | 2.17E-4    | 3.190723   | 0.0016068
+instance-2       | 2.2E-4     | 2.744054   | 0.0016068
+;
+
+
+
+allAggsInlineGrouped
+required_capability: exponential_histogram_minmax_support
+
+FROM exp_histo_sample 
+ | INLINE STATS min = MIN(responseTime), max = MAX(responseTime), p75 = PERCENTILE(responseTime,75) BY instance
+ | EVAL p75 = ROUND(p75, 7) // rounding to avoid floating point precision issues
+ | KEEP instance, min, max, p75
+ | SORT instance
+ | Limit 15
+;
+
+instance:keyword          | min:double | max:double | p75:double
+dummy-empty               | null       | null       | null
+dummy-full                | -100.0     | 50.0       | 10.6666667
+dummy-negative_only       | -50.0      | -1.0       | -12.8729318
+dummy-no_zero_bucket      | -100.0     | 50.0       | 10.6666667
+dummy-positive_only       | 1.0        | 50.0       | 34.7656715
+dummy-zero_count_only     | 0.0        | 0.0        | 0.0
+dummy-zero_threshold_only | null       | null       | null
+instance-0                | 2.4E-4     | 6.786232   | 0.2608237
+instance-0                | 2.4E-4     | 6.786232   | 0.2608237
+instance-0                | 2.4E-4     | 6.786232   | 0.2608237
+instance-0                | 2.4E-4     | 6.786232   | 0.2608237
+instance-0                | 2.4E-4     | 6.786232   | 0.2608237
+instance-0                | 2.4E-4     | 6.786232   | 0.2608237
+instance-0                | 2.4E-4     | 6.786232   | 0.2608237
+instance-0                | 2.4E-4     | 6.786232   | 0.2608237
+;
+
+
+
+allAggsOnEmptyHistogram
+required_capability: exponential_histogram_minmax_support
+
+FROM exp_histo_sample | WHERE instance == "dummy-empty"
+ | STATS min = MIN(responseTime), max = MAX(responseTime), p75 = PERCENTILE(responseTime,75)
+ | KEEP min, max, p75
+;
+
+min:double | max:double | p75:double
+NULL       | NULL       | NULL
+;
+
+
+
 ungroupedPercentiles
 required_capability: exponential_histogram_percentiles_support
 
@@ -27,6 +94,8 @@ p0:double | p50:double | p99:double | p100:double
 2.17E-4   | 0.0016965  | 0.9472324  | 6.786232
 ;
 
+
+
 groupedPercentiles
 required_capability: exponential_histogram_percentiles_support
 
@@ -42,3 +111,62 @@ instance-0       | 2.4E-4    | 0.0211404  | 1.0432946  | 6.786232
 instance-1       | 2.17E-4   | 6.469E-4   | 0.1422151  | 3.190723
 instance-2       | 2.2E-4    | 6.469E-4   | 0.0857672  | 2.7059714542564097
 ;
+
+
+
+percentileOnEmptyHistogram
+required_capability: exponential_histogram_percentiles_support
+
+FROM exp_histo_sample | WHERE instance == "dummy-empty"
+ | STATS  p50 = PERCENTILE(responseTime,50)
+ | KEEP p50
+;
+
+p50:double
+NULL
+;
+
+
+
+ungroupedMinMax
+required_capability: exponential_histogram_minmax_support
+
+FROM exp_histo_sample | WHERE NOT STARTS_WITH(instance, "dummy") 
+ | STATS min = MIN(responseTime),  max = MAX(responseTime)
+ | KEEP min, max
+;
+
+min:double | max:double
+2.17E-4    | 6.786232
+;
+
+
+
+groupedMinMax
+required_capability: exponential_histogram_minmax_support
+
+FROM exp_histo_sample | WHERE NOT STARTS_WITH(instance, "dummy") 
+ | STATS min = MIN(responseTime),  max = MAX(responseTime) BY instance
+ | KEEP instance, min, max
+ | SORT instance
+;
+
+instance:keyword | min:double | max:double
+instance-0       | 2.4E-4     | 6.786232
+instance-1       | 2.17E-4    | 3.190723
+instance-2       | 2.2E-4     | 2.744054
+;
+
+
+
+minMaxOnEmptyHistogram
+required_capability: exponential_histogram_minmax_support
+
+FROM exp_histo_sample | WHERE instance == "dummy-empty"
+ | STATS  min = MIN(responseTime), max = MAX(responseTime)
+ | KEEP min, max
+;
+
+min:double | max:double
+NULL       | NULL
+;

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/action/EsqlCapabilities.java

@@ -1562,6 +1562,16 @@ public enum Cap {
          */
         EXPONENTIAL_HISTOGRAM_TOPN(EXPONENTIAL_HISTOGRAM_FEATURE_FLAG),
 
+        /**
+         * Support for exponential_histogram type in PERCENTILES aggregation.
+         */
+        EXPONENTIAL_HISTOGRAM_PERCENTILES_SUPPORT(EXPONENTIAL_HISTOGRAM_FEATURE_FLAG),
+
+        /**
+         * Support for exponential_histogram type in MIN/MAX aggregation.
+         */
+        EXPONENTIAL_HISTOGRAM_MINMAX_SUPPORT(EXPONENTIAL_HISTOGRAM_FEATURE_FLAG),
+
         /**
          * Create new block when filtering OrdinalBytesRefBlock
          */
@@ -1652,11 +1662,6 @@ public enum Cap {
 
         FULL_TEXT_FUNCTIONS_ACCEPT_NULL_FIELD,
 
-        /**
-         * Support for exponential_histogram type in PERCENTILES aggregation.
-         */
-        EXPONENTIAL_HISTOGRAM_PERCENTILES_SUPPORT(EXPONENTIAL_HISTOGRAM_FEATURE_FLAG),
-
         /**
          * Support for the temporary work to eventually allow FIRST to work with null and multi-value fields, among other things.
          */

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/aggregate/Max.java

@@ -17,6 +17,7 @@
 import org.elasticsearch.compute.aggregation.MaxIpAggregatorFunctionSupplier;
 import org.elasticsearch.compute.aggregation.MaxLongAggregatorFunctionSupplier;
 import org.elasticsearch.compute.data.AggregateMetricDoubleBlockBuilder;
+import org.elasticsearch.compute.data.ExponentialHistogramBlock;
 import org.elasticsearch.xpack.esql.EsqlIllegalArgumentException;
 import org.elasticsearch.xpack.esql.core.expression.Expression;
 import org.elasticsearch.xpack.esql.core.expression.Literal;
@@ -30,6 +31,7 @@
 import org.elasticsearch.xpack.esql.expression.function.FunctionType;
 import org.elasticsearch.xpack.esql.expression.function.Param;
 import org.elasticsearch.xpack.esql.expression.function.scalar.convert.FromAggregateMetricDouble;
+import org.elasticsearch.xpack.esql.expression.function.scalar.histogram.ExtractHistogramComponent;
 import org.elasticsearch.xpack.esql.expression.function.scalar.multivalue.MvMax;
 import org.elasticsearch.xpack.esql.planner.ToAggregator;
 
@@ -59,7 +61,18 @@ public class Max extends AggregateFunction implements ToAggregator, SurrogateExp
     );
 
     @FunctionInfo(
-        returnType = { "boolean", "double", "integer", "long", "date", "date_nanos", "ip", "keyword", "unsigned_long", "version" },
+        returnType = {
+            "boolean",
+            "double",
+            "integer",
+            "long",
+            "date",
+            "date_nanos",
+            "ip",
+            "keyword",
+            "unsigned_long",
+            "version",
+            "exponential_histogram" },
         description = "The maximum value of a field.",
         type = FunctionType.AGGREGATE,
         examples = {
@@ -88,7 +101,8 @@ public Max(
                 "keyword",
                 "text",
                 "unsigned_long",
-                "version" }
+                "version",
+                "exponential_histogram" }
         ) Expression field
     ) {
         this(source, field, Literal.TRUE, NO_WINDOW);
@@ -126,7 +140,7 @@ public Max replaceChildren(List<Expression> newChildren) {
     protected TypeResolution resolveType() {
         return TypeResolutions.isType(
             field(),
-            dt -> SUPPLIERS.containsKey(dt) || dt == DataType.AGGREGATE_METRIC_DOUBLE,
+            dt -> SUPPLIERS.containsKey(dt) || dt == DataType.AGGREGATE_METRIC_DOUBLE || dt == DataType.EXPONENTIAL_HISTOGRAM,
             sourceText(),
             DEFAULT,
             "boolean",
@@ -135,13 +149,14 @@ protected TypeResolution resolveType() {
             "string",
             "version",
             "aggregate_metric_double",
+            "exponential_histogram",
             "numeric except counter types"
         );
     }
 
     @Override
     public DataType dataType() {
-        if (field().dataType() == DataType.AGGREGATE_METRIC_DOUBLE) {
+        if (field().dataType() == DataType.AGGREGATE_METRIC_DOUBLE || field().dataType() == DataType.EXPONENTIAL_HISTOGRAM) {
             return DataType.DOUBLE;
         }
         return field().dataType().noText();
@@ -167,6 +182,14 @@ public Expression surrogate() {
                 window()
             );
         }
+        if (field().dataType() == DataType.EXPONENTIAL_HISTOGRAM) {
+            return new Max(
+                source(),
+                ExtractHistogramComponent.create(source(), field(), ExponentialHistogramBlock.Component.MAX),
+                filter(),
+                window()
+            );
+        }
         return field().foldable() ? new MvMax(source(), field()) : null;
     }
 }

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/aggregate/Min.java

@@ -17,6 +17,7 @@
 import org.elasticsearch.compute.aggregation.MinIpAggregatorFunctionSupplier;
 import org.elasticsearch.compute.aggregation.MinLongAggregatorFunctionSupplier;
 import org.elasticsearch.compute.data.AggregateMetricDoubleBlockBuilder;
+import org.elasticsearch.compute.data.ExponentialHistogramBlock;
 import org.elasticsearch.xpack.esql.EsqlIllegalArgumentException;
 import org.elasticsearch.xpack.esql.core.expression.Expression;
 import org.elasticsearch.xpack.esql.core.expression.Literal;
@@ -30,6 +31,7 @@
 import org.elasticsearch.xpack.esql.expression.function.FunctionType;
 import org.elasticsearch.xpack.esql.expression.function.Param;
 import org.elasticsearch.xpack.esql.expression.function.scalar.convert.FromAggregateMetricDouble;
+import org.elasticsearch.xpack.esql.expression.function.scalar.histogram.ExtractHistogramComponent;
 import org.elasticsearch.xpack.esql.expression.function.scalar.multivalue.MvMin;
 import org.elasticsearch.xpack.esql.planner.ToAggregator;
 
@@ -88,7 +90,8 @@ public Min(
                 "keyword",
                 "text",
                 "unsigned_long",
-                "version" }
+                "version",
+                "exponential_histogram" }
         ) Expression field
     ) {
         this(source, field, Literal.TRUE, NO_WINDOW);
@@ -126,7 +129,7 @@ public Min withFilter(Expression filter) {
     protected TypeResolution resolveType() {
         return TypeResolutions.isType(
             field(),
-            dt -> SUPPLIERS.containsKey(dt) || dt == DataType.AGGREGATE_METRIC_DOUBLE,
+            dt -> SUPPLIERS.containsKey(dt) || dt == DataType.AGGREGATE_METRIC_DOUBLE || dt == DataType.EXPONENTIAL_HISTOGRAM,
             sourceText(),
             DEFAULT,
             "boolean",
@@ -135,13 +138,14 @@ protected TypeResolution resolveType() {
             "string",
             "version",
             "aggregate_metric_double",
+            "exponential_histogram",
             "numeric except counter types"
         );
     }
 
     @Override
     public DataType dataType() {
-        if (field().dataType() == DataType.AGGREGATE_METRIC_DOUBLE) {
+        if (field().dataType() == DataType.AGGREGATE_METRIC_DOUBLE || field().dataType() == DataType.EXPONENTIAL_HISTOGRAM) {
             return DataType.DOUBLE;
         }
         return field().dataType().noText();
@@ -167,6 +171,14 @@ public Expression surrogate() {
                 window()
             );
         }
+        if (field().dataType() == DataType.EXPONENTIAL_HISTOGRAM) {
+            return new Min(
+                source(),
+                ExtractHistogramComponent.create(source(), field(), ExponentialHistogramBlock.Component.MIN),
+                filter(),
+                window()
+            );
+        }
         return field().foldable() ? new MvMin(source(), field()) : null;
     }
 }

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/scalar/histogram/ExtractHistogramComponent.java

@@ -21,6 +21,7 @@
 import org.elasticsearch.xpack.esql.core.expression.Expression;
 import org.elasticsearch.xpack.esql.core.expression.Expressions;
 import org.elasticsearch.xpack.esql.core.expression.FoldContext;
+import org.elasticsearch.xpack.esql.core.expression.Literal;
 import org.elasticsearch.xpack.esql.core.tree.NodeInfo;
 import org.elasticsearch.xpack.esql.core.tree.Source;
 import org.elasticsearch.xpack.esql.core.type.DataType;
@@ -37,6 +38,7 @@
 import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.isFoldable;
 import static org.elasticsearch.xpack.esql.core.expression.TypeResolutions.isType;
 import static org.elasticsearch.xpack.esql.core.type.DataType.DOUBLE;
+import static org.elasticsearch.xpack.esql.core.type.DataType.INTEGER;
 import static org.elasticsearch.xpack.esql.core.type.DataType.LONG;
 
 /**
@@ -78,6 +80,10 @@ private ExtractHistogramComponent(StreamInput in) throws IOException {
         this(Source.readFrom((PlanStreamInput) in), in.readNamedWriteable(Expression.class), in.readNamedWriteable(Expression.class));
     }
 
+    public static Expression create(Source source, Expression field, ExponentialHistogramBlock.Component component) {
+        return new ExtractHistogramComponent(source, field, new Literal(source, component.ordinal(), INTEGER));
+    }
+
     Expression field() {
         return field;
     }

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/analysis/VerifierTests.java

@@ -1152,7 +1152,8 @@ public void testAggregateOnCounter() {
             error("FROM test | STATS min(network.bytes_in)", tsdb),
             equalTo(
                 "1:19: argument of [min(network.bytes_in)] must be"
-                    + " [boolean, date, ip, string, version, aggregate_metric_double or numeric except counter types],"
+                    + " [boolean, date, ip, string, version, aggregate_metric_double,"
+                    + " exponential_histogram or numeric except counter types],"
                     + " found value [network.bytes_in] type [counter_long]"
             )
         );
@@ -1161,7 +1162,8 @@ public void testAggregateOnCounter() {
             error("FROM test | STATS max(network.bytes_in)", tsdb),
             equalTo(
                 "1:19: argument of [max(network.bytes_in)] must be"
-                    + " [boolean, date, ip, string, version, aggregate_metric_double or numeric except counter types],"
+                    + " [boolean, date, ip, string, version, aggregate_metric_double, exponential_histogram"
+                    + " or numeric except counter types],"
                     + " found value [network.bytes_in] type [counter_long]"
             )
         );

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/aggregate/MaxErrorTests.java

@@ -37,7 +37,8 @@ protected Matcher<String> expectedTypeErrorMatcher(List<Set<DataType>> validPerP
                 false,
                 validPerPosition,
                 signature,
-                (v, p) -> "boolean, date, ip, string, version, aggregate_metric_double or numeric except counter types"
+                (v, p) -> "boolean, date, ip, string, version, aggregate_metric_double, "
+                    + "exponential_histogram or numeric except counter types"
             )
         );
     }

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/aggregate/MaxOverTimeErrorTests.java

@@ -37,7 +37,8 @@ protected Matcher<String> expectedTypeErrorMatcher(List<Set<DataType>> validPerP
                 false,
                 validPerPosition,
                 signature,
-                (v, p) -> "boolean, date, ip, string, version, aggregate_metric_double or numeric except counter types"
+                (v, p) -> "boolean, date, ip, string, version, aggregate_metric_double, "
+                    + "exponential_histogram or numeric except counter types"
             )
         );
     }