Ensure float size is correct when encoding to pg values

[scsmithr]

Description

See PRQL/prql#3669 (comment)

It looks like we're passing Float8 in the postgres row descriptor, but the column values are actually f32.

I don't have a reproducible sql example yet...

[vrongmeal]

TL;DR: We don't support binary formatting as of now.

Querying using the rust client (query method) assumes the data we get is in binary format, but currently, we only support text format.

let rows = client.query("select 11111111", &[]).await?;
let val: i64 = rows[0].get(0);

The above code works since the string 11111111 has 8 bytes (equivalent to int8). Any other string length would fail.

This would work if the test uses simple_query and parse the string as f64 but that would require implementing a different test client in prql.

[eitsupi]

Thanks for looking at this! Maybe this issue sfackler/rust-postgres#882?

[vrongmeal]

Thanks for looking at this! Maybe this issue sfackler/rust-postgres#882?

Yeah, this issue is related.