Professional software engineer, musician, gamer, stoic, democratic socialist

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Cake day: July 2nd, 2023

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  • I’m on a strong streak with my Japanese self study. Been going for over a year and I’m somewhere around N4-N3 level. It’s very rewarding to understand long conversations, but it also feels like progress is slow. My grammar is pretty good now, but learning vocabulary and kanji is like a Sysyphian quest.

    I’d say I usually get in at least 30 minutes of listening practice every day. I’m still not speaking much, but I think this is OK. I’ve heard VR chat is a good resource for that, but the timezone mismatch makes it pretty hard.

    Overall I recommend immersion based study with a strong emphasis on input (listening + reading) before doing much output. Duolingo is a waste of time if you’re serious about approaching fluency. I’ve never seen a single comprehensive product that actually works for learning Japanese. You have to consume native materials, and there are some good tools that make it easier, but you need to be a bit savvy to stitch them all together into a cohesive workflow.










  • tatterdemalion@programming.devOPtoProgrammer Humor@programming.devSQLite
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    27 days ago

    There is a subtle scenario with read-modify-write transactions in MVCC where SQLite lacks some grace (in my opinion).

    In MVCC, transactions work with a point-in-time (read “between atomic transactions”) consistent “read snapshot” of the database.

    Consider this example:

    1. Transaction A begins and reads from table foo.
    2. Transaction B begins and updates table foo.
    3. Both transactions commit.

    There is no conflict here because these transactions are isolated from each other via the snapshot mechanism. Transaction A’s read snapshot is immutable and will not see any writes from transaction B, even if they are happening concurrently.

    Now what happens in this example (from the OP):

    1. Transaction A begins and reads from table foo.
    2. Transaction B begins and updates table foo.
    3. Transaction B commits.
    4. Transaction A tries to update foo.

    This is a true conflict because both transactions are trying to write to foo, and transaction A’s writes might be based on what it just read. There is no consistent way for A to proceed, because B already wrote to foo, invalidating A’s read snapshot.

    So SQLite handles this by returning an error to A, effectively requiring A to restart the transaction.

    There are other ways this could be handled though. The DB could optimistically retry the transaction for you. There is even a special BEGIN IMMEDIATE; statement that it could use to proactively take a write lock on foo so that the transaction doesn’t get starved by other writers. But SQLite puts all of the responsibility on users to handle this.

    I’m not an expert, so there could be a very good reason that SQLite works this way, but it feels a bit annoying as a user.

    I don’t actually know off the top of my head how PostgresQL handles this particular scenario.