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Comment by chii | Hacker News Reader

> SQLite is all you need if it really is all you need.

most use cases are really capable of being satisfied by sqlite, but the "architect" imagines they need more (or is preparing for the potential).

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> the "architect" imagines they need more (or is preparing for the potential)

I guess I am one of those "architects" that imagines they need an actual date/time storage class instead of some stringly-typed text column that I hope will contain a parsable ISO8601 datetime string when I try to read it back.

Hipp said that it will never be added because it will bloat the size of the embedded object. Because that is what SQLite was designed for: single-user embedded databases. Like the address book on your phone.

In fairness, sqlite is perfectly happy with Julian dates or Unix timestamps (that’s the affinity of a column typed “datetime” in non-strict mode) and timestamp(tz) are nothing to write home about except in complaint.

so now we've traded a text column for an int column that still can't validate that the number is actually externally consistent with the real world.

Is there an invalid unix timestamp? What is there to validate?

Well for one we should probably validate that the number is smaller than the total life of the physical universe.

SQLite will gladly store a u64::MAX as a "unix timestamp" despite it being about 300x larger than the number of seconds that the universe and everything in it has existed.

Try reading that back in any application date/time code and your app probably crashes immediately.

And how would you validate that? Which arbitrary cutoff do you find reasonable?

And if your app crashes on an input like that, you should pick a different date Library or stop and rethink your coding skills.

> SQLite will gladly store a u64::MAX as a "unix timestamp"

SQLite does not support unsigned integers.

> Try reading that back in any application date/time code and your app probably crashes immediately.

Postgres will happily ingest and produce dates in the 280th millenium, which will also crash your application if its datetime type can’t handle that shrug.

You can add a check constraint that your field passes through SQLite’s datetime functions and it’ll be clamped between the years 0 and 9999. Or you can put in your own limits matching your application layer, or your application’s business logic. That’s what check constrains are for (amongst other things).

> SQLite does not support unsigned integers.

omg you're right. Another example of SQLite's type-flimsyness.

> You can add a check constraint

So now we're just layering on our own brittle validation and runtime checks to make up for sqlite's woeful deficiency supporting even basic domain data types.

> omg you're right. Another example of SQLite's type-flimsyness.

You're just firing on all the bullshit cylinders in your little motorised gish gallop aren't you?

The only RDBMS in widespread use which supports unsigned integers is mysql. Not postgres, not oracle, not sql server, not db2, not snowflake, not databricks.

> So now we're just layering on our own brittle validation and runtime checks to make up for sqlite's woeful deficiency supporting even basic domain data types.

Ah yes, the "brittle validation" of actually validating the thing you purported to care about two comments ago. Amazing.

> I guess I am one of those "architects" that imagines they need an actual date/time storage class instead of some stringly-typed text column that I hope will contain a parsable ISO8601 datetime string when I try to read it back.

To be honest if you're using JSON at any point in your stack you have the same issue.

I was such a big sqlite fan that I used it for my data-intensive startup. Once I actually started scaling it up I ran into crippling file system race conditions. This was because we were hosted on a distributed file system in the cloud which I learned is very very bad for sqlite.

So I had to migrate the production db under live load from sqlite to mysql which was a quite ...intense week. I still like sqlite but I'd be wary of using it again for a usecase like mine.

SQLite creators explicitly warn against using SQLite on a networked file system btw.

If you could conceivably use multiple processes at once to access the database, and not just as an edge case, you need something more than sqlite.

Sqlite does support multi-process access correctly, but the performance is abysmal as it locks the entire file for any write transaction. Client/server databases have much smarter concurrency.

It’s perfectly fine if your write throughput is low, especially in wal mode. Multiprocess does not actually change much if anything, even in multithreaded mode you want every thread to have its own connection and to have a good handle on who is writing when.

Regardless, it's a sign sqlite is not right for you. You should start with postgres if you aren't sure your application will always be good with sqlite. It'll save you a migration, and doesn't really cost anything to start your project with postgres instead of sqlite.

There is an interesting pattern SyncLite (https://github.com/syncliteio/SyncLite) attempts to solve to bring the best of both SQLite and Postgres with one or more SQLite databases directly serving the application while SyncLite replicating/consolidating data from all those SQLite databases into a centralized PostgreSQL database..

It sounds like a solution trying to sell itself. While you probably can do something like that and it might even be useful for some applications, I can't imagine it's a very good generic solution - you probably want to do it yourself if you want to do it.

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