1 files changed, 11 insertions, 2 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/runtime/commands/QueryCommand.java b/src/main/java/com/google/devtools/build/lib/runtime/commands/QueryCommand.java
index ec8ae85db4..8817c71ce8 100644
--- a/src/main/java/com/google/devtools/build/lib/runtime/commands/QueryCommand.java
+++ b/src/main/java/com/google/devtools/build/lib/runtime/commands/QueryCommand.java
@@ -45,6 +45,7 @@ import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.common.options.OptionsParser;
 import com.google.devtools.common.options.OptionsProvider;
+import java.io.BufferedOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.nio.channels.ClosedByInterruptException;
@@ -156,7 +157,15 @@ public final class QueryCommand implements BlazeCommand {
 
     expr = queryEnv.transformParsedQuery(expr);
 
-    OutputStream out = env.getReporter().getOutErr().getOutputStream();
+    OutputStream out;
+    if (formatter.canBeBuffered()) {
+      // There is no particular reason for the 16384 constant here, except its a multiple of the
+      // gRPC buffer size. We mainly don't want to send each label individually because the output
+      // stream is connected to gRPC, and every write gets converted to one gRPC call.
+      out = new BufferedOutputStream(env.getReporter().getOutErr().getOutputStream(), 16384);
+    } else {
+      out = env.getReporter().getOutErr().getOutputStream();
+    }
     ThreadSafeOutputFormatterCallback<Target> callback;
     if (streamResults) {
       disableAnsiCharactersFiltering(env);
@@ -217,7 +226,7 @@ public final class QueryCommand implements BlazeCommand {
             result,
             targets,
             formatter,
-            env.getReporter().getOutErr().getOutputStream(),
+            out,
             queryOptions.aspectDeps.createResolver(env.getPackageManager(), env.getReporter()));
       } catch (ClosedByInterruptException | InterruptedException e) {
         env.getReporter().handle(Event.error("query interrupted"));