I want to implement reporting framework. Selection of the ID's of
items takes very long time, because queries are quite complicated. So
i want to avoid constantly triggering time consuming select stored
procedures by caching the results in some persistent way.

I have choosen external tables as the most performant way of storing,
retrieving, droping cached information. I want store ID's and
RowNumber returned by time consuming query in external table created
at runtime of stored procedure. The only problem is that EXECUTE
STATEMENT 'Create T' || intNum || ' external file ....' creates table,
but it is not ready to use in insert statement immediatelly. ID are
just used with join with another tables to fullfill report
requirements, rownum is used for fast paging.

I dont want to use "normal" indexed table with reportID for
implementing cache mechanizm, because inserting of 70.000 of records
takes 9-20s where as that same operation with external table takes 1s,
deleting 3s while in external table it is just drop.

It is possible to solve it?