protected void convertJoinToSMBJoin(
    JoinOperator joinOp,
    SortBucketJoinProcCtx smbJoinContext) throws SemanticException {
    MapJoinOperator mapJoinOp = convertJoinToBucketMapJoin(joinOp, smbJoinContext);
    SMBMapJoinOperator smbMapJoinOp =
        convertBucketMapJoinToSMBJoin(mapJoinOp, smbJoinContext);
    smbMapJoinOp.setConvertedAutomaticallySMBJoin(true);
  }
Whether this table is eligible for a sort-merge join.

@param pctx                  parse context
@param op                    map join operator being considered
@param joinTree              join tree being considered
@param alias                 table alias in the join tree being checked
@param pos                   position of the table
@param sortColumnsFirstTable The names and order of the sorted columns for the first table.
                             It is not initialized when pos = 0.
@return
@throws SemanticException
ql/src/java/org/apache/hadoop/hive/ql/optimizer/AbstractSMBJoinProc.java