On: Siren Call of SQLite on the Server

[wmanley]

You definitely want WAL mode (unless you’re accessing SQLite over NFS). It’s only not the default for backwards compatibility. I’d enable:

PRAGMA journal_mode = WAL; PRAGMA foreign_keys = 1; PRAGMA mmap_size = 1099511627776;

Unless you know a reason that you can’t (like NFS or using a 32-bit cpu).

[znpy → wmanley]

> Unless you know a reason that you can’t (like NFS or using a 32-bit cpu).

interesting, why there's that limitation when nfs and a 32-bit cpu are involved?

[wmanley → znpy]

WAL mode requires shared memory, so doesn’t work over the network.

mmap_size = 1TiB requires 1TiB of address space per connection. This is fine on 64-bit, unless you have millions of connections. Doesn’t work with 32-bit (4GiB) address space.

You want mmap_size to be greater than the size of your database. If you know your database will be small then you could set it to a smaller number, but you could still become address space constrained with many connections.