single instance question

[dougg0k]

Hi,

I found your lib this week and wanted to know.

Does your lib always behave as single instance in case I import it multiple times from the same setup?

If not, is there a recommended way to cache it?
Asking this because I tried caching different dbs libs before and it gave weird side effects.

Thanks.

[mceachen]

Every new better-sqlite3 instance should be considered a running database -- so make sure you manage your instances as singletons appropriately.

In case we're talking at ends, for this example:

const bs = require("better-sqlite3")
const a = bs("/tmp/test.db")
const b = bs("/tmp/test.db")

a and b will not share any caches or any other metadata. They should return the same data, though, thanks to SQLite.

[dougg0k]

right.

that's why I mentioned setup, because that would be the return of the new Database(dbpath).

I opened the question because I saw this but wasnt sure. #234 (comment)

[dougg0k]

Here it mentions that multi connections can cause a huge overhead #234 (comment)

Maybe a solution like this, could help.

const dbCache = {};

function setupDb(dbPath: string) {
	const db = new Database(dbPath);
        ...
	if (!dbCache[dbPath]) {
		dbCache[dbPath] = db;
	}
	return dbCache[dbPath];
}

To give some context. I never used better-sqlite3 before, hence why asking. I will migrate a project to sql, right after I finish another part of the project migration.

[mceachen]

That certainly may be applicable for some, but I don't think it's the responsibility of this library to manage singletons or instance lifecycles.

[dougg0k]

Not much on the responsability, but if it does actually improve or decrease performance. And the tradeoffs if any.