Why? Because HANA’s optimizer relies on fresh statistics. If your stats were from the last system copy three months ago, HANA would generate a brilliant execution plan for a dataset that no longer existed. You’d see a query take 12 seconds that should take 200 milliseconds.
But here is the practical kicker that most blogs missed: Even after conversion, your F table still contained REQUEST_GUID entries for every single data load. That’s right—every DTP request left a forensic trail inside the fact table. sap bw 7.4 practical guide pdf 28
Now go check your RSDD_HDB logs. You’ll probably find an index that hasn’t been rebuilt since 2018. You’d see a query take 12 seconds that
For years, a quiet, dog-eared document circulated among senior BW consultants: a PDF simply titled "SAP BW 7.4 Practical Guide." And within that guide, was the threshold. Now go check your RSDD_HDB logs
If you see Column Search taking longer than Join Processing , you have a classic 7.4 problem: Your HANA model is emulating a row-store.
In BW 3.5 and 7.0, your fact tables (F-fact tables and E-fact tables) were designed to minimize disk I/O for row-based databases like Oracle or DB6. But on HANA, row storage is poison. It destroys parallelization.
Run transaction ST04 (DBACOCKPIT). Look for "High Wait Time on Locks." Then, run RSRT with the technical name of your slowest query. Turn on "HANA Execution Details."