diff --git a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/Classification.java b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/Classification.java
index fef3cb0fb33..a7eefe199d4 100644
--- a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/Classification.java
+++ b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/Classification.java
@@ -241,6 +241,7 @@ public class Classification implements DataFrameAnalysis {
             params.put(PREDICTION_FIELD_TYPE, predictionFieldType);
         }
         params.put(NUM_CLASSES, fieldInfo.getCardinality(dependentVariable));
+        params.put(TRAINING_PERCENT.getPreferredName(), trainingPercent);
         return params;
     }
 
diff --git a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/Regression.java b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/Regression.java
index 0d40ef6ba35..824d4f95a17 100644
--- a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/Regression.java
+++ b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/Regression.java
@@ -163,6 +163,7 @@ public class Regression implements DataFrameAnalysis {
         if (predictionFieldName != null) {
             params.put(PREDICTION_FIELD_NAME.getPreferredName(), predictionFieldName);
         }
+        params.put(TRAINING_PERCENT.getPreferredName(), trainingPercent);
         return params;
     }
 
diff --git a/x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/ClassificationTests.java b/x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/ClassificationTests.java
index d7285fb8600..14cbf338687 100644
--- a/x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/ClassificationTests.java
+++ b/x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/ClassificationTests.java
@@ -17,7 +17,6 @@ import org.elasticsearch.index.mapper.BooleanFieldMapper;
 import org.elasticsearch.index.mapper.KeywordFieldMapper;
 import org.elasticsearch.index.mapper.NumberFieldMapper;
 import org.elasticsearch.xpack.core.ml.AbstractBWCSerializationTestCase;
-import org.hamcrest.Matchers;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -201,31 +200,43 @@ public class ClassificationTests extends AbstractBWCSerializationTestCase<Classi
 
         assertThat(
             new Classification("foo").getParams(fieldInfo),
-            Matchers.<Map<String, Object>>allOf(
-                hasEntry("dependent_variable", "foo"),
-                hasEntry("class_assignment_objective", Classification.ClassAssignmentObjective.MAXIMIZE_MINIMUM_RECALL),
-                hasEntry("num_top_classes", 2),
-                hasEntry("prediction_field_name", "foo_prediction"),
-                hasEntry("prediction_field_type", "bool"),
-                hasEntry("num_classes", 10L)));
+            equalTo(
+                org.elasticsearch.common.collect.Map.of(
+                    "dependent_variable", "foo",
+                    "class_assignment_objective", Classification.ClassAssignmentObjective.MAXIMIZE_MINIMUM_RECALL,
+                    "num_top_classes", 2,
+                    "prediction_field_name", "foo_prediction",
+                    "prediction_field_type", "bool",
+                    "num_classes", 10L,
+                    "training_percent", 100.0)));
         assertThat(
             new Classification("bar").getParams(fieldInfo),
-            Matchers.<Map<String, Object>>allOf(
-                hasEntry("dependent_variable", "bar"),
-                hasEntry("class_assignment_objective", Classification.ClassAssignmentObjective.MAXIMIZE_MINIMUM_RECALL),
-                hasEntry("num_top_classes", 2),
-                hasEntry("prediction_field_name", "bar_prediction"),
-                hasEntry("prediction_field_type", "int"),
-                hasEntry("num_classes", 20L)));
+            equalTo(
+                org.elasticsearch.common.collect.Map.of(
+                    "dependent_variable", "bar",
+                    "class_assignment_objective", Classification.ClassAssignmentObjective.MAXIMIZE_MINIMUM_RECALL,
+                    "num_top_classes", 2,
+                    "prediction_field_name", "bar_prediction",
+                    "prediction_field_type", "int",
+                    "num_classes", 20L,
+                    "training_percent", 100.0)));
         assertThat(
-            new Classification("baz").getParams(fieldInfo),
-            Matchers.<Map<String, Object>>allOf(
-                hasEntry("dependent_variable", "baz"),
-                hasEntry("class_assignment_objective", Classification.ClassAssignmentObjective.MAXIMIZE_MINIMUM_RECALL),
-                hasEntry("num_top_classes", 2),
-                hasEntry("prediction_field_name", "baz_prediction"),
-                hasEntry("prediction_field_type", "string"),
-                hasEntry("num_classes", 30L)));
+            new Classification("baz",
+                BoostedTreeParams.builder().build() ,
+                null,
+                null,
+                null,
+                50.0,
+                null).getParams(fieldInfo),
+            equalTo(
+                org.elasticsearch.common.collect.Map.of(
+                    "dependent_variable", "baz",
+                    "class_assignment_objective", Classification.ClassAssignmentObjective.MAXIMIZE_MINIMUM_RECALL,
+                    "num_top_classes", 2,
+                    "prediction_field_name", "baz_prediction",
+                    "prediction_field_type", "string",
+                    "num_classes", 30L,
+                    "training_percent", 50.0)));
     }
 
     public void testRequiredFieldsIsNonEmpty() {
diff --git a/x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/RegressionTests.java b/x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/RegressionTests.java
index 68ff2f71fb9..c7fbcadad45 100644
--- a/x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/RegressionTests.java
+++ b/x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/RegressionTests.java
@@ -19,7 +19,6 @@ import java.io.IOException;
 import java.util.Map;
 import java.util.Collections;
 
-import static org.hamcrest.Matchers.allOf;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.equalTo;
@@ -132,7 +131,20 @@ public class RegressionTests extends AbstractBWCSerializationTestCase<Regression
     public void testGetParams() {
         assertThat(
             new Regression("foo").getParams(null),
-            allOf(hasEntry("dependent_variable", "foo"), hasEntry("prediction_field_name", "foo_prediction")));
+            equalTo(org.elasticsearch.common.collect.Map.of(
+                "dependent_variable", "foo",
+                "prediction_field_name", "foo_prediction",
+                "training_percent", 100.0)));
+        assertThat(
+            new Regression("foo",
+                BoostedTreeParams.builder().build(),
+                null,
+                50.0,
+                null).getParams(null),
+            equalTo(org.elasticsearch.common.collect.Map.of(
+                "dependent_variable", "foo",
+                "prediction_field_name", "foo_prediction",
+                "training_percent", 50.0)));
     }
 
     public void testRequiredFieldsIsNonEmpty() {
diff --git a/x-pack/plugin/ml/qa/native-multi-node-tests/src/test/java/org/elasticsearch/xpack/ml/integration/ExplainDataFrameAnalyticsIT.java b/x-pack/plugin/ml/qa/native-multi-node-tests/src/test/java/org/elasticsearch/xpack/ml/integration/ExplainDataFrameAnalyticsIT.java
index 708d52cdf50..6dd6a553ad3 100644
--- a/x-pack/plugin/ml/qa/native-multi-node-tests/src/test/java/org/elasticsearch/xpack/ml/integration/ExplainDataFrameAnalyticsIT.java
+++ b/x-pack/plugin/ml/qa/native-multi-node-tests/src/test/java/org/elasticsearch/xpack/ml/integration/ExplainDataFrameAnalyticsIT.java
@@ -10,17 +10,21 @@ import org.elasticsearch.action.bulk.BulkRequestBuilder;
 import org.elasticsearch.action.bulk.BulkResponse;
 import org.elasticsearch.action.index.IndexRequest;
 import org.elasticsearch.action.support.WriteRequest;
+import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.xpack.core.ml.action.ExplainDataFrameAnalyticsAction;
 import org.elasticsearch.xpack.core.ml.dataframe.DataFrameAnalyticsConfig;
 import org.elasticsearch.xpack.core.ml.dataframe.DataFrameAnalyticsSource;
+import org.elasticsearch.xpack.core.ml.dataframe.analyses.BoostedTreeParams;
 import org.elasticsearch.xpack.core.ml.dataframe.analyses.Classification;
+import org.elasticsearch.xpack.core.ml.dataframe.analyses.Regression;
 import org.elasticsearch.xpack.core.ml.dataframe.analyses.OutlierDetection;
 import org.elasticsearch.xpack.core.ml.utils.QueryProvider;
 
 import java.io.IOException;
 
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.lessThan;
 import static org.hamcrest.Matchers.lessThanOrEqualTo;
 
 public class ExplainDataFrameAnalyticsIT extends MlNativeDataFrameAnalyticsIntegTestCase {
@@ -81,4 +85,41 @@ public class ExplainDataFrameAnalyticsIT extends MlNativeDataFrameAnalyticsInteg
 
         assertThat(explainResponse.getMemoryEstimation().getExpectedMemoryWithoutDisk().getKb(), lessThanOrEqualTo(1024L));
     }
+
+    public void testTrainingPercentageIsApplied() throws IOException {
+        String sourceIndex = "test-training-percentage-applied";
+        RegressionIT.indexData(sourceIndex, 100, 0);
+
+        DataFrameAnalyticsConfig config = new DataFrameAnalyticsConfig.Builder()
+            .setId("dfa-training-100-" + sourceIndex)
+            .setSource(new DataFrameAnalyticsSource(new String[] { sourceIndex },
+                QueryProvider.fromParsedQuery(QueryBuilders.matchAllQuery()),
+                null))
+            .setAnalysis(new Regression(RegressionIT.DEPENDENT_VARIABLE_FIELD,
+                BoostedTreeParams.builder().build(),
+                null,
+                100.0,
+                null))
+            .buildForExplain();
+
+        ExplainDataFrameAnalyticsAction.Response explainResponse = explainDataFrame(config);
+
+        ByteSizeValue allDataUsedForTraining = explainResponse.getMemoryEstimation().getExpectedMemoryWithoutDisk();
+
+        config = new DataFrameAnalyticsConfig.Builder()
+            .setId("dfa-training-50-" + sourceIndex)
+            .setSource(new DataFrameAnalyticsSource(new String[] { sourceIndex },
+                QueryProvider.fromParsedQuery(QueryBuilders.matchAllQuery()),
+                null))
+            .setAnalysis(new Regression(RegressionIT.DEPENDENT_VARIABLE_FIELD,
+                BoostedTreeParams.builder().build(),
+                null,
+                50.0,
+                null))
+            .buildForExplain();
+
+        explainResponse = explainDataFrame(config);
+
+        assertThat(explainResponse.getMemoryEstimation().getExpectedMemoryWithoutDisk(), lessThan(allDataUsedForTraining));
+    }
 }
diff --git a/x-pack/plugin/ml/qa/native-multi-node-tests/src/test/java/org/elasticsearch/xpack/ml/integration/RegressionIT.java b/x-pack/plugin/ml/qa/native-multi-node-tests/src/test/java/org/elasticsearch/xpack/ml/integration/RegressionIT.java
index 3536971bcf2..b5c6d3698ee 100644
--- a/x-pack/plugin/ml/qa/native-multi-node-tests/src/test/java/org/elasticsearch/xpack/ml/integration/RegressionIT.java
+++ b/x-pack/plugin/ml/qa/native-multi-node-tests/src/test/java/org/elasticsearch/xpack/ml/integration/RegressionIT.java
@@ -23,7 +23,6 @@ import org.elasticsearch.xpack.core.ml.dataframe.analyses.Regression;
 import org.junit.After;
 
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -40,10 +39,10 @@ public class RegressionIT extends MlNativeDataFrameAnalyticsIntegTestCase {
 
     private static final String NUMERICAL_FEATURE_FIELD = "feature";
     private static final String DISCRETE_NUMERICAL_FEATURE_FIELD = "discrete-feature";
-    private static final String DEPENDENT_VARIABLE_FIELD = "variable";
-    private static final List<Double> NUMERICAL_FEATURE_VALUES = Collections.unmodifiableList(Arrays.asList(1.0, 2.0, 3.0));
-    private static final List<Long> DISCRETE_NUMERICAL_FEATURE_VALUES = Collections.unmodifiableList(Arrays.asList(10L, 20L, 30L));
-    private static final List<Double> DEPENDENT_VARIABLE_VALUES = Collections.unmodifiableList(Arrays.asList(10.0, 20.0, 30.0));
+    static final String DEPENDENT_VARIABLE_FIELD = "variable";
+    private static final List<Double> NUMERICAL_FEATURE_VALUES = org.elasticsearch.common.collect.List.of(1.0, 2.0, 3.0);
+    private static final List<Long> DISCRETE_NUMERICAL_FEATURE_VALUES = org.elasticsearch.common.collect.List.of(10L, 20L, 30L);
+    private static final List<Double> DEPENDENT_VARIABLE_VALUES = org.elasticsearch.common.collect.List.of(10.0, 20.0, 30.0);
 
     private String jobId;
     private String sourceIndex;
@@ -399,7 +398,7 @@ public class RegressionIT extends MlNativeDataFrameAnalyticsIntegTestCase {
         this.destIndex = sourceIndex + "_results";
     }
 
-    private static void indexData(String sourceIndex, int numTrainingRows, int numNonTrainingRows) {
+    static void indexData(String sourceIndex, int numTrainingRows, int numNonTrainingRows) {
         client().admin().indices().prepareCreate(sourceIndex)
             .addMapping("_doc",
                 NUMERICAL_FEATURE_FIELD, "type=double",