question: public static Operator generateBranchPlan ( AkibanInformationSchema ais , Table table ) { final Operator indexScan = generateIndexScan ( ais , table ) ; final Schema schema = SchemaCache . globalSchema ( ais ) ; PrimaryKey pkey = table . getPrimaryKeyIncludingInternal ( ) ; IndexRowType indexType = schema . indexRowType ( pkey . getIndex ( ) ) ; return generateBranchPlan ( table , indexScan , indexType ) ; }
target:  Scan a group starting with Primary Key of a table,  then get all of the children (if any). Primary key  is set as parameters to the query context.  Generates a plan: Branch Lookup  Index Scan (table, pk-> ?[, ?...])