Today I had to remind myself how simple the solutions can be sometimes.
I’m working on optimising the QVD loads in a significant incremental load process, some simple changes dropped our reload time from 1hr15 to 41mins (30mins is SQL) but I figured I could strip out some time downstream as well by loading some binary flags in the initial QVDs.
The first flag is used in a downstream reduction QVD but I was scratching my head when it came to optimising it as a simple WHERE flag =1 causes the load to loose its optimisation.
But when the solution came to me it was so simple I kicked myself:
load 1 as flag
Now I can simply use WHERE EXISTS (flag) and the load is optimised.