diff --git a/build.xml b/build.xml
index 6adb0420d0..e59896754e 100644
--- a/build.xml
+++ b/build.xml
@@ -219,6 +219,7 @@
             classpath="${build.lib}/antlr-3.2.jar"
             fork="true"
             failonerror="true">
+         <jvmarg value="-Xmx512M" />
          <arg value="${build.src.java}/org/apache/cassandra/cql/Cql.g" />
          <arg value="-fo" />
          <arg value="${build.src.gen-java}/org/apache/cassandra/cql/" />