Create BENCHMARKING.md

BENCHMARKING.md

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+##To determine whether any changes are a notable loss in performance:
+
+1. Start with the old approach
+2. Use a fresh database
+3. Use a large extract, such as France, Germany, Britain, etc. Too small of PBFs may be entirely cached in RAM and not representative of planet performance
+4. Time the extract, ensuring you have the desired zoom level as set in .env
+5. Switch to the new approach and use a fresh database once again
+6. Quickstart.log will have all the time logs.
+7. If necessary, run an update as well to see if your approach can keep up with live updates on the chosen interval. Currently, weekly updates are the target.
+
+##To determine whether your changes in SQL are lossless:
+
+It is recommended to use the "sqldiff" tool to compare mbtiles.
+
+`sqldiff --table tiles new.mbtiles old.mbtiles`
+
+This will compare on just the tiles table, ensuring for each zoom, x, y that the tile data is the same between both mbtiles. If sqldiff returns nothing, it means the results are identical.