As the table is updated, queries that define the join indexes are re processed to obtain the records for updating {HEAD ~ the join indexes}, wherein {TAIL ~ one or more common joins} are identified among the join indexes, each common join is materialized only once in a common spool file, and the common spool file is used to materialize one or more rows for updating the join indexes 
As the table is updated , queries that define the join indexes are re processed to obtain the records for updating { HEAD ~ the join indexes } , wherein { TAIL ~ one or more common joins } are identified among the join indexes , each common join is materialized only once in a common spool file , and the common spool file is used to materialize one or more rows for updating the join indexes
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH