CBO: debug logging OOMs

hive> source xcross.sql;
OK
Time taken: 0.837 seconds
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
        at java.util.Arrays.copyOf(Arrays.java:3332)
        at java.lang.AbstractStringBuilder.expandCapacity(AbstractStringBuilder.java:137)
        at java.lang.AbstractStringBuilder.ensureCapacityInternal(AbstractStringBuilder.java:121)
        at java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:421)
        at java.lang.StringBuilder.append(StringBuilder.java:136)
        at org.apache.hadoop.hive.ql.parse.ASTNode.dump(ASTNode.java:111)
        at org.apache.hadoop.hive.ql.parse.ASTNode.dump(ASTNode.java:119)
        at org.apache.hadoop.hive.ql.parse.ASTNode.dump(ASTNode.java:119)
        at org.apache.hadoop.hive.ql.parse.ASTNode.dump(ASTNode.java:119)
        at org.apache.hadoop.hive.ql.parse.ASTNode.dump(ASTNode.java:119)

          this.ctx.setCboInfo("Plan optimized by CBO.");
          this.ctx.setCboSucceeded(true);
          LOG.debug(newAST.dump());
          }