Remove optional seed from ES|QL SAMPLE

Author: jan-elastic

x-pack/plugin/esql/compute/src/main/java/org/elasticsearch/compute/operator/SampleOperator.java

@@ -27,16 +27,16 @@
 
 public class SampleOperator implements Operator {
 
-    public record Factory(double probability, int seed) implements OperatorFactory {
+    public record Factory(double probability) implements OperatorFactory {
 
         @Override
         public SampleOperator get(DriverContext driverContext) {
-            return new SampleOperator(probability, seed);
+            return new SampleOperator(probability);
         }
 
         @Override
         public String describe() {
-            return "SampleOperator[probability = " + probability + ", seed = " + seed + "]";
+            return "SampleOperator[probability = " + probability + "]";
         }
     }
 
@@ -58,10 +58,10 @@ public String describe() {
     private long collectNanos;
     private long emitNanos;
 
-    private SampleOperator(double probability, int seed) {
+    private SampleOperator(double probability) {
         finished = false;
         outputPages = new ArrayDeque<>();
-        SplittableRandom random = new SplittableRandom(seed);
+        SplittableRandom random = new SplittableRandom();
         randomSamplingIterator = new RandomSamplingQuery.RandomSamplingIterator(Integer.MAX_VALUE, probability, random::nextInt);
         // Initialize the iterator to the next document that needs to be sampled.
         randomSamplingIterator.nextDoc();

x-pack/plugin/esql/src/main/antlr/EsqlBaseParser.g4

@@ -312,5 +312,5 @@ completionCommand
     ;
 
 sampleCommand
-    : DEV_SAMPLE probability=decimalValue seed=integerValue?
+    : DEV_SAMPLE probability=decimalValue
     ;

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/optimizer/rules/logical/PushDownAndCombineSample.java

@@ -62,8 +62,7 @@ protected LogicalPlan rule(Sample sample, LogicalOptimizerContext context) {
         var child = sample.child();
         if (child instanceof Sample sampleChild) {
             var probability = combinedProbability(context, sample, sampleChild);
-            var seed = combinedSeed(context, sample, sampleChild);
-            plan = new Sample(sample.source(), probability, seed, sampleChild.child());
+            plan = new Sample(sample.source(), probability, sampleChild.child());
         } else if (child instanceof Enrich
             || child instanceof Eval
             || child instanceof Filter
@@ -82,22 +81,4 @@ private static Expression combinedProbability(LogicalOptimizerContext context, S
         var childProbability = (double) Foldables.valueOf(context.foldCtx(), child.probability());
         return Literal.of(parent.probability(), parentProbability * childProbability);
     }
-
-    private static Expression combinedSeed(LogicalOptimizerContext context, Sample parent, Sample child) {
-        var parentSeed = parent.seed();
-        var childSeed = child.seed();
-        Expression seed;
-        if (parentSeed != null) {
-            if (childSeed != null) {
-                var seedValue = (int) Foldables.valueOf(context.foldCtx(), parentSeed);
-                seedValue ^= (int) Foldables.valueOf(context.foldCtx(), childSeed);
-                seed = Literal.of(parentSeed, seedValue);
-            } else {
-                seed = parentSeed;
-            }
-        } else {
-            seed = childSeed;
-        }
-        return seed;
-    }
 }

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/optimizer/rules/physical/local/PushSampleToSource.java

@@ -33,9 +33,6 @@ protected PhysicalPlan rule(SampleExec sample, LocalPhysicalOptimizerContext ctx
             }
 
             var sampleQuery = new RandomSamplingQueryBuilder((double) Foldables.valueOf(ctx.foldCtx(), sample.probability()));
-            if (sample.seed() != null) {
-                sampleQuery.seed((int) Foldables.valueOf(ctx.foldCtx(), sample.seed()));
-            }
 
             fullQuery.filter(sampleQuery);