I have built multiple models based on Sales Order, Item, Billing and Delivery. My Sales Item has around 3.85 million records and when I expose it to SAC, the performance is really really bad around 3 whole minutes. In all the models I use a lot of Left Outer joins instead of associations. Based on my understanding associations are converted into joins while executing, so using explicit joins should not hurt performance.
While there are around 3.8 million records, the performance seem very bad takes around 3.46 minutes to load the summarized data. Are there anything that I can look for (Common mistakes) that I can correct to improve performance? or list of performance suggestions?