IN and EXISTS often produce the same result, but when negated and dealing with NULL values, they behave differently.

Today I learned how to run a webserver in Google Colab, without needing external services like ngrok. I'm using Dagster here as an example but any webserver should work.

Presentation I gave at the Dagster Community Meeting on the 21st of September, 2021 on how to use Dagster for machine learning purposes, with an explanation on why we chose that instead of Airflow.

1. Not letting it double. I was impatient and kept refreshing it even if i didn't see any (or very little) activity. I had to wait longer.
2. Put it in the fridge too early. I put it in the fridge on day 7, while there was still no activity (probably due to point one). I had to put it back to ambient temperature to fix it.
3. Little oxygen available. I was putting a lid on top of the container. While it was just resting there unscrewed, I think that it reduced the amount of air going inside the container too much. I fixed it by replacing the lid with a kitchen towel secured with an elastic.
4. Too much water. I was hydrating it too much. While 100-110% hydration should be ok, it seems to grow much stronger now that i reduced it to 90%.
5. Changed flour too early. Changing flour is ok, but i did it one of the first days of the starter. I think that might have messed up things as I went from a 100% rye to a mix of whole wheat and strong white flour.

Note: for this recipe you need a pizza stone to get best results. In alternative, you can use a pan that can withstand high temperatures.

Preparation time: 3h

Rest time: 12h (but the dough is usable up to 36h later)

Cooking time: 3-4 mins (depending on the oven)

Ingredients (for 4 Pizzas)

• 400g 00 (Pizza) flour
• 200g Manitoba flour
• 1-2g dried yeast (the least yeast you put, the longer it will take to grow, but it will grow)
• 360ml water (room temperature or colder if you want a longer leavening)
• 40g extra virgin olive oil
• 12g salt

Preparation

1. Mix all the flour with the yeast in a large bowl. Add 70% of water and mix manually.
2. Let rest for 30min.
3. Add all the salt shaking it around and then poking it into the dough with wet fingers. Add a bit of the remaining water and keep mixing until it gets all togheter.
4. Add the olive oil and mix together. Let it rest again for 30 min.
5. Cover the table with a little bit of 00 flour (not too much) and flip the dough onto the table. Let it rest there for 30 min.
6. Gently (we don't want air to get out) help it rest a bit more on the table, and then when it's a bit larger fold it into 2. Then on the other side fold again (reinforcement fold). Let it rest for 1h.
7. Cut dough into 4 portions
8. Roll each mini-dough on itself from the bottom to do a little ball (with air in the middle) and let it rest on the fridge overnight. Take it out just before making the pizza (when the oven is already hot).

Cooking

Pizza requires very high temperatures (>300 celsius). Home ovens typically reach 250-260, but the grid on top of the oven is hotter, for this reason you need to put the static oven to max, put pizza stone on the top shelf as close as you can to the grid, and let it get hot (~45 min).

Prepare the dough on top of some flour. Use your hands only. First use your index and middle finger and design the crust, then slowly start tapping in the middle with all your fingers to slightly expand. Flip the dough, and do the same. Then put the dough on the back of your hands, and make it rotate with your thumbs while you expand with the fingers.

Once ready, take out the stone, put the dough on top of it, extend it a bit more if needed. Add tomato sauce, and all toppings. Put it in the oven for 3~4 mins and take it out. Serve hot.