CockroachDB supports the PostgreSQL protocol but connection fails due to "IntervalStyle": "iso_8601"

[bmisiak]

Hi.

I tried connecting to CockroachDB just now and hit a little snafu. It supports the PostgreSQL protocol, but it apparently requires IntervalStyle to be set to postgres instead of iso_8601.

SQLx sets it to the latter here:

sqlx/sqlx-core/src/postgres/connection.rs

Line 108 in d269506

("IntervalStyle", "iso_8601"),

Which results in:

Error: invalid value for parameter "IntervalStyle": "iso_8601"

Is supporting postgres here easy for SQLx, or would it be a significant headache? I was worried about INTERVAL fields but they seem to be returned to the consumer as strings, since conversion to Duration impls haven't been written yet.

When I naively changed the field to postgres in my fork, connection succeeded and queries work.

[abonander]

Yeah, that really only matters if we actually support encoding and decoding intervals which we don't currently. Neither chrono nor time support parsing a Duration type, which would be the Rust equivalent. We could manually implement it using the Postgres style but that's a bit involved.

@mehcode is there another reason you have IntervalStyle set?

[mehcode]

I'd accept just removing the explicit set of IntervalStyle. My plan was to add a PgInterval type but we can (and probably) should add parsing for "postgres" format instead of the newer "iso8601" format.

---

I'm not sure I'm comfortable claiming to support CockroachDB. If we can make this change and it works 100%, great, but we probably need to enumerate a "Database Support" chart like Rust does for platforms (perhaps on the Readme). We could have "Tier 1" being guaranteed and "Tier 2" being "someone told us this works". I'd mark CockroachDB under "Tier 2".

[bmisiak]

@mehcode For sure, agreed. I have tested it and it seems to be working beautifully with SQLx after removing IntervalStyle.

.. as well as other ordinary PostgreSQL clients:

I'll submit a PR to remove it. It's only a SET SESSION IntervalStyle = 'iso_8601' away after all.