Hacker News Reader

Comment by kasey_junk | Hacker News Reader

Largely for driver coverage. Postgres drivers are available in tons of languages so by being wire compatible you can skip all that work.

View on HN

Yes. I don't see the harm in the PostgreSQL wire protocol becoming a defacto standard for sending SQL statements over a network connection and getting results back.

SQL itself is only a vague standard these days, as almost every single database has its own dialect. The only ones that are the same are MariaDB and MySQL... and that doesn't count. [1] And I don't see this situation changing in the medium term, or ever, really.

[1] ... because the first is the fork of the second.

This. I’ll take the pg protocol over OCI and especially ODBC any day.

There's a small amount of harm because Postgres doesn't currently support request multiplexing and so its wire protocol doesn't have any facility for it. This pushes other databases to inherit one of Postgres's few true weak points.

I take it that opening multiple database connections to the same server is not usually viable? I realize there are usually limits to open sockets / file descriptors and such, and that multiple connections will consume more memory on each end. Are there problems beyond that?

It's usually (but not always) viable and it's ultimately what one ends up doing. You're right about the drawbacks. One additional drawback is the setup time for opening new connections (network round-trip, re-authenticating, etc.).

If I’m not wrong, I think this situation has changed with the latest Postgres release:

https://www.postgresql.org/docs/current/libpq-pipeline-mode....

Interesting! I was not aware of this, thanks for sharing. I'll have to look into it in detail to determine whether it's actually pipelining or multiplexing because pipelining is still problematic, since it's subject to head-of-line blocking (one expensive request blocks everyone from getting their responses until it's completed).

it's not multiplexing afaik. you will still have to process commands in the order they were put on the wire.

You're gonna have some similar thing no matter what gets settled on, unless there's a flawless protocol out there but those are pretty rare in my experience.

I think the comparison is more like "is having an ad-hoc semi-standard wire protocol built around the postgres one better than having none at all?" and I think the answer is yes.

But it's not like there's an authority making this choice for everyone. If you think something else is better then use it in your tools and push for it. Postgres is ancient, open source, widely used and adapted for many different use cases. I think those all make it hard to beat in just a practical "worse is better" type way, but I also think people saying "no. we can do better" is good too, esp when they demonstrate it.

I agree with everything you said! I was reacting to "I don't see the harm" specifically. Ultimately, I think that with a few improvements to the Postgres protocol, settling on it wouldn't even be a "worse is better" outcome.

My understanding is that SQLite tries to maintain compatibility with Postgres in the subset of SQL that it supports. So if this program reaches a reasonable level of maturity I would love to be able to use it with pre-existing products that were designed to use Postgres as a backend, to substitute SQLite as a drop-in replacement. One might hope that this could work for products that don't use Postgres's more cutting-edge features.

SQLite's lack of type safety makes me hesitate to use it as a drop-in replacement for Postgres.

I wouldn't use SQLite as a drop-in replacement either but, in case you haven't seen it, SQLite did add "strict mode" for better enforcement of type safety: https://sqlite.org/src/wiki?name=StrictMode

They fixed that a couple of versions ago: https://www.sqlite.org/stricttables.html

> Postgres drivers are available in tons of languages

So are SQLite drivers (and MySQL and all the other top-10/top-20 databases).

Why add un-necessary abstraction ?

Why add an un-necessary layer with bugs and edge-cases that you will subsequently waste hours of your life debugging ?

Plus, if we are talking about drivers, then surely if you're going to be using SQLite, you should be using SQLite drivers because they will be inherently simpler and smaller than the Postgres ones because of the much reduced feature-set of SQLite.

> What SQLite3 driver out there allows you to talk over a network connection to a remote database?

(Replied here because I can't reply to your point below)

Maybe that's because, as per the SQLite website[1], SQLite was never intended to be used as a client/server database !!!

I would argue that by attempting to "square peg round hole" SQLite into being a network database, you are only opening yourself up for unknown troubles down the road.

There are many excellent client/server databases out there (including the postgres referred to here). If you need that functionality you should be using the right tool for the job, there's no need to shoehorn SQLite into it.

[1] https://www.sqlite.org/whentouse.html

> Plus, if we are talking about drivers, then surely if you're going to be using SQLite, you should be using SQLite drivers because they will be inherently simpler and smaller than the Postgres ones because of the much reduced feature-set of SQLite.

What SQLite3 driver out there allows you to talk over a network connection to a remote database? Not any one that I've ever used.

> I would argue that by attempting to "square peg round hole" SQLite into being a network database, you are only opening yourself up for unknown troubles down the road.

It depends a lot on what you're using the remote connectivity for.

I think I have a pretty good understanding of SQLite's strengths+capabilities, enough to understand when it can replace a traditional RDBMS for a back-end service. I wouldn't build a solution where multiple clients are connecting to the DB remotely - but sometimes I want the convenience of connecting to the DB remotely for observability/troubleshooting. This is something that's trivial with traditional RDBMSs, and a bit painful with SQLite.

Exposing the SQLite DB over the network for occasional interactive use seems quite useful to me.

It's also useful if you initially built an application SQLite and are transitioning to Postgres.

Reply on news.ycombinator.com