TheTank

5 ms·

1. 1.▲
   by TheTank 2y ago

   Hey of course, happy to meet and exchange about our fun projects. You can send me an email using the address in the above comment and we'll setup something!
2. 2.▲
   by TheTank 2y ago

   Hey, yes I can do that. I will brush this up, package all the bits (3d files, pcb files, code etc), and add to github. On another note, would you happen to live in London? If you really want to try this I could hand you one which will save
3. 3.▲
   by TheTank 2y ago

   I'm afraid not because it would only run on the device so you'd need to make one using a raspberry pi pico and the exact same display (Pimoroni display pack) as it leverages its graphics library to draw text and shapes. So far, th
4. 4.▲
   by TheTank 2y ago

   Thanks for the feedback. Yes it takes some practice to be able to read and understand an orderbook, and I find that visualisations help a lot, so does making your own derived metrics (for example calculating vwap prices, distance to fair in
5. 5.▲
   by TheTank 2y ago

   It's a tough question because most of what I learned was on the job and I don't really remember books specifically on the topic. It also depends on what product and market you are trading, and on what channels (on exchange, over t
6. 6.▲
   by TheTank 2y ago

   There isn't any library for the trading UI or graphics elements. The only library in this case was the display graphics library which allows to draw simple primitives such as squares, lines, circles, text, etc. [1] The UI is a bunch of
7. 7.▲
   by TheTank 2y ago

   They did continue participating but it's true that this became a sort of electric train where daddy buys it for the children and ends up playing the most with it. The trading game did not capture their interest further than watching co
8. 8.▲
   by TheTank 2y ago

   You're right and besides that, it's not an interesting game for them. I continued involving him using the same platform, but we made more age-appropriate games. It's easy to upload a different game over a USB cable so I could
9. 9.▲
   by TheTank 2y ago

   Author here. Thanks for reading this post. I had fun making this and thought the path that led me to this might be interesting for others. I’m really interested in feedback and ideas on things I could improve and add. I found this really in
10. 10.▲
    by TheTank 6y ago

    Author here. You are right this is convoluted and confusing. I wanted to write an informal introduction to options using a more tangible example for those who are put off by the maths but still would like to gain an intuitive understanding.
11. 11.▲
    by TheTank 6y ago

    Congrats on launching. It looks like it’s only email login. Do you have an idea when you will release Oauth logins?
12. 12.▲
    by TheTank 6y ago

    Thanks! Indeed we are still light on available aggregations. Right now we are focused on building a fast infrastructure to support them, for example Swissmap / "rosti" for keyed aggregations. Next steps will include multi-pas
13. 13.▲
    by TheTank 6y ago

    Thanks for your question! The main value proposition is raw performance which translates into hardware efficiency and ultimately, costs at scale. To get a rough idea of how we compare, you could try to running `select cab_type, count() from
14. 14.▲
    by TheTank 6y ago

    The trips table takes 313GB. QuestDB is not an in-memory DB. The data sits on SSD EBS volumes.
15. 15.▲
    by TheTank 6y ago

    Tanks for the feedback. WHERE queries are slow indeed. This is not because of the load but rather because WHERE clauses are not yet implemented under the fast path. Currently they run under an old model which is single-threaded which is why
16. 16.▲
    by TheTank 6y ago

    Will do. Thanks for offering help!
17. 17.▲
    by TheTank 6y ago

    Yes, this is part of the roadmap. Right now, we don't have any interesting query to showcase that would use these columns - they are here because they are part of the original dataset and we are keeping them for when we demo further re
18. 18.▲
    by TheTank 6y ago

    Very accurate! Regarding the theme of joins, I would just add that QuestDB also has a concept called SYMBOL which allows to store repetitive strings into a table as an integer in the background, while letting the user manipulate strings. Th
19. 19.▲
    by TheTank 6y ago

    Thanks for the feedback, we'll look into it!
20. 20.▲
    by TheTank 6y ago

    We will definitely make QuestDB distributed in the near future. Today, our focus is to extract the maximum performance out of a single node. If we start scaling out too early, it may become harder to improve performance after the fact. So a
21. 21.▲
    by TheTank 6y ago

    One step beyond good Java GCs is to write fully zero-GC Java code. The advantage of it is complete control over your performance which means your software is going to be consistently fast. The disadvantage is that it is relatively difficult
22. 22.▲
    by TheTank 6y ago

    Thanks for sharing. Do I assume correctly that this tool takes in dividend expectations and not only announced dividends? Building a portfolio around dividend expectations is definitely useful for many reasons. But predicting dividends is h
23. 23.▲
    by TheTank 6y ago

    Thanks for sharing. Do I understand correctly that this requires loading the whole file in memory along with an ordered list of keys? Or is it just the first n bytes that are loaded in memory? If the former, then it seems very expensive in
24. 24.▲
    by TheTank 6y ago

    I find the concept interesting and I can see real applications for something like this (delaying someone's access to a file). For example, one could use that to disseminate press releases ahead of time without actually revealing the co
25. 25.▲
    by TheTank 6y ago

    Interesting project. Out of curiosity, why did you compare against kdb+ since the models are very different? KDB is mostly used for in-memory time-series while your seem to be a graph-oriented DB. Also, why did you choose to build your own
26. 26.▲
    by TheTank 6y ago

    Thank you for your kind comment! We would consider offloading to a GPU when the time is right. It feels right to fully utilise CPU capabilities before jumping to GPU.
27. 27.▲
    by TheTank 6y ago

    In the future, we will release other products with features geared towards enterprises. We don't think that having our code open will harm the business. On the contrary, it will hopefully help us gain some popularity by allowing any de
28. 28.▲
    by TheTank 6y ago

    Window functions are in draft, we will release them imminently. We will support moving averages. In fact we plan to support generic multi-pass and window functions. Having multi-pass will allow you to do things like `select sum(x -sum(x)) f
29. 29.▲
    by TheTank 6y ago

    QuestDB | Head of Dev Rel / community manager |Remote, London/SF QuestDB is a an open source SQL database to process time-series, faster. The founding team comes from low-latency trading; fast software and timestamped data are par
30. 30.▲
    by TheTank 7y ago

    It is a good strategy (and an interesting product). The execution side might be complex for retail traders. Execution is particularly important because although you get a cheap structure (selling one leg, buying the other), you end up cross