Myk

• Oct 11th, 2006

 

Are you lookuping flat file or database table? Generaly, sorted joiner is more efective on flat files than lookup, because sorted joiner uses merge join and cashes less rows. Lookup cashes always whole file. If the file is not sorted, it can be comparable.Lookups into database table can be effective if the database can return sorted data fast and the amount of data is small, because lookup can create whole cash in memory. If database responses slowly or big amount of data are processed, lookup cache initialization can be really slow (lookup waits for database and stores cashed data on discs). Then it can be better use sorted joiner, which throws data to output as reads them on input.