In the past it was not possible to load a mapping table directly from a QVD file. We had to use some workarounds to break the optimized load like:
Mapping_Map: Mapping LOAD Field1, Field2 FROM qvdFile.qvd (qvd) WHERE 1=1;
Mappping_Map: Mapping LOAD Field1, Field2, 1 as Field_temp FROM qvdFile.qvd (qvd); DROP FIELD Field_temp FROM Mapping_Map;
just loading the fields to a temporary table and then using a RESIDENT LOAD.
Also have a look at the excellent article from Rob Wunderlich on several QVD-topics (“QVD Questions and answers”) where he also mentioned this issue.
Although I have not read any offiicial announcement on that topic a direct load from a QVD file into a mapping load is now possible in QV 10 SR2.
Just a little testing script, if you want to ensure if it really works:
Map: LOAD * INLINE [ F1, F2 A, A-mapped B, B-mapped C, C-mapped ]; STORE Map INTO Map.qvd(qvd); DROP TABLE Map; // The real testing scenario starts here ... Mapping_Map: Mapping Load * FROM Map.qvd (qvd); Transactions: Load TransLineID, TransID, ApplyMap('Mapping_Map', Pick(Ceil(3*Rand1),'A','B','C'),'n/a') as Dim1, Pick(Ceil(6*Rand1),'a','b','c','d','e','f') as Dim2; Load Rand() as Rand1, IterNo() as TransLineID, RecNo() as TransID Autogenerate 1000 While Rand()<=0.5 or IterNo()=1;
Good News! Although there is now some need to improve our existing scripts to improve the load time by some seconds