diff --git a/Documentation/config-gerrit.txt b/Documentation/config-gerrit.txt
index 6acb2d6a00..36b0e31370 100644
--- a/Documentation/config-gerrit.txt
+++ b/Documentation/config-gerrit.txt
@@ -823,6 +823,15 @@ changes is updated.
 +
 Default is 1.
 
+[[changeMerge.interactiveThreadPoolSize]]changeMerge.interactiveThreadPoolSize::
++
+Maximum size of the thread pool in which the mergeability flag of open
+changes is updated, when processing interactive user requests (e.g.
+pushes to refs/for/*). Set to 0 or negative to share the pool for
+background mergeability checks.
++
+Default is 1.
+
 [[commentlink]]
 === Section commentlink
 
diff --git a/gerrit-pgm/src/main/java/com/google/gerrit/pgm/Reindex.java b/gerrit-pgm/src/main/java/com/google/gerrit/pgm/Reindex.java
index 2b0850e2cf..b8649629e4 100644
--- a/gerrit-pgm/src/main/java/com/google/gerrit/pgm/Reindex.java
+++ b/gerrit-pgm/src/main/java/com/google/gerrit/pgm/Reindex.java
@@ -44,6 +44,7 @@ import com.google.gerrit.server.cache.h2.DefaultCacheFactory;
 import com.google.gerrit.server.change.ChangeKindCache;
 import com.google.gerrit.server.change.MergeabilityChecker;
 import com.google.gerrit.server.change.MergeabilityChecksExecutor;
+import com.google.gerrit.server.change.MergeabilityChecksExecutor.Priority;
 import com.google.gerrit.server.change.PatchSetInserter;
 import com.google.gerrit.server.config.CanonicalWebUrl;
 import com.google.gerrit.server.config.CanonicalWebUrlProvider;
@@ -290,11 +291,20 @@ public class Reindex extends SiteProgram {
 
     @Provides
     @Singleton
-    @MergeabilityChecksExecutor
+    @MergeabilityChecksExecutor(Priority.BACKGROUND)
     public WorkQueue.Executor createMergeabilityChecksExecutor(
         WorkQueue queues) {
       return queues.createQueue(1, "MergeabilityChecks");
     }
+
+    @Provides
+    @Singleton
+    @MergeabilityChecksExecutor(Priority.INTERACTIVE)
+    public WorkQueue.Executor createInteractiveMergeabilityChecksExecutor(
+        @MergeabilityChecksExecutor(Priority.BACKGROUND)
+          WorkQueue.Executor bg) {
+      return bg;
+    }
   }
 
   private int indexAll() throws Exception {
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/MergeabilityChecker.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/MergeabilityChecker.java
index e6d8b69d2e..0734d12496 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/MergeabilityChecker.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/MergeabilityChecker.java
@@ -34,6 +34,7 @@ import com.google.gerrit.reviewdb.client.RefNames;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.change.MergeabilityChecksExecutor.Priority;
 import com.google.gerrit.server.change.Mergeable.MergeableInfo;
 import com.google.gerrit.server.git.MetaDataUpdate;
 import com.google.gerrit.server.git.ProjectConfig;
@@ -85,11 +86,13 @@ public class MergeabilityChecker implements GitReferenceUpdatedListener {
     private List<Project.NameKey> projects;
     private boolean force;
     private boolean reindex;
+    private boolean interactive;
 
     private Check() {
       changes = Lists.newArrayListWithExpectedSize(1);
       branches = Lists.newArrayListWithExpectedSize(1);
       projects = Lists.newArrayListWithExpectedSize(1);
+      interactive = true;
     }
 
     public Check addChange(Change change) {
@@ -99,11 +102,13 @@ public class MergeabilityChecker implements GitReferenceUpdatedListener {
 
     public Check addBranch(Branch.NameKey branch) {
       branches.add(branch);
+      interactive = false;
       return this;
     }
 
     public Check addProject(Project.NameKey project) {
       projects.add(project);
+      interactive = false;
       return this;
     }
 
@@ -119,7 +124,12 @@ public class MergeabilityChecker implements GitReferenceUpdatedListener {
       return this;
     }
 
+    private ListeningExecutorService getExecutor() {
+      return interactive ? interactiveExecutor : backgroundExecutor;
+    }
+
     public CheckedFuture<?, IOException> runAsync() {
+      final ListeningExecutorService executor = getExecutor();
       ListenableFuture<List<Change>> getChanges;
       if (branches.isEmpty() && projects.isEmpty()) {
         getChanges = Futures.immediateFuture(changes);
@@ -201,7 +211,8 @@ public class MergeabilityChecker implements GitReferenceUpdatedListener {
   private final ChangeControl.GenericFactory changeControlFactory;
   private final Provider<Mergeable> mergeable;
   private final ChangeIndexer indexer;
-  private final ListeningExecutorService executor;
+  private final ListeningExecutorService backgroundExecutor;
+  private final ListeningExecutorService interactiveExecutor;
   private final MergeabilityCheckQueue mergeabilityCheckQueue;
   private final MetaDataUpdate.Server metaDataUpdateFactory;
 
@@ -211,7 +222,10 @@ public class MergeabilityChecker implements GitReferenceUpdatedListener {
       IdentifiedUser.GenericFactory identifiedUserFactory,
       ChangeControl.GenericFactory changeControlFactory,
       Provider<Mergeable> mergeable, ChangeIndexer indexer,
-      @MergeabilityChecksExecutor Executor executor,
+      @MergeabilityChecksExecutor(Priority.BACKGROUND)
+        Executor backgroundExecutor,
+      @MergeabilityChecksExecutor(Priority.INTERACTIVE)
+        Executor interactiveExecutor,
       MergeabilityCheckQueue mergeabilityCheckQueue,
       MetaDataUpdate.Server metaDataUpdateFactory) {
     this.tl = tl;
@@ -220,7 +234,10 @@ public class MergeabilityChecker implements GitReferenceUpdatedListener {
     this.changeControlFactory = changeControlFactory;
     this.mergeable = mergeable;
     this.indexer = indexer;
-    this.executor = MoreExecutors.listeningDecorator(executor);
+    this.backgroundExecutor =
+        MoreExecutors.listeningDecorator(backgroundExecutor);
+    this.interactiveExecutor =
+        MoreExecutors.listeningDecorator(interactiveExecutor);
     this.mergeabilityCheckQueue = mergeabilityCheckQueue;
     this.metaDataUpdateFactory = metaDataUpdateFactory;
   }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/MergeabilityChecksExecutor.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/MergeabilityChecksExecutor.java
index 5a26086768..632e6ac053 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/MergeabilityChecksExecutor.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/MergeabilityChecksExecutor.java
@@ -28,4 +28,9 @@ import java.lang.annotation.Retention;
 @Retention(RUNTIME)
 @BindingAnnotation
 public @interface MergeabilityChecksExecutor {
+  public enum Priority {
+    BACKGROUND, INTERACTIVE;
+  }
+
+  Priority value();
 }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/MergeabilityChecksExecutorModule.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/MergeabilityChecksExecutorModule.java
index 102cfafe83..96c83d36ab 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/MergeabilityChecksExecutorModule.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/MergeabilityChecksExecutorModule.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.change;
 
+import com.google.gerrit.server.change.MergeabilityChecksExecutor.Priority;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.git.WorkQueue;
 import com.google.inject.AbstractModule;
@@ -22,7 +23,6 @@ import com.google.inject.Singleton;
 
 import org.eclipse.jgit.lib.Config;
 
-
 /** Module providing the {@link MergeabilityChecksExecutor}. */
 public class MergeabilityChecksExecutorModule extends AbstractModule {
   @Override
@@ -31,11 +31,27 @@ public class MergeabilityChecksExecutorModule extends AbstractModule {
 
   @Provides
   @Singleton
-  @MergeabilityChecksExecutor
+  @MergeabilityChecksExecutor(Priority.BACKGROUND)
   public WorkQueue.Executor createMergeabilityChecksExecutor(
       @GerritServerConfig Config config,
       WorkQueue queues) {
     int poolSize = config.getInt("changeMerge", null, "threadPoolSize", 1);
     return queues.createQueue(poolSize, "MergeabilityChecks");
   }
+
+  @Provides
+  @Singleton
+  @MergeabilityChecksExecutor(Priority.INTERACTIVE)
+  public WorkQueue.Executor createMergeabilityChecksExecutor(
+      @GerritServerConfig Config config,
+      WorkQueue queues,
+      @MergeabilityChecksExecutor(Priority.BACKGROUND)
+        WorkQueue.Executor backgroundExecutor) {
+    int poolSize =
+        config.getInt("changeMerge", null, "interactiveThreadPoolSize", 1);
+    if (poolSize <= 0) {
+      return backgroundExecutor;
+    }
+    return queues.createQueue(poolSize, "InteractiveMergeabilityChecks");
+  }
 }