Redo edgedb basic types to inherit from builtin types

[fantix]

• edgedb.Tuple is tuple
  • weakref.ref() will stop working on edgedb.Tuple objects.
• edgedb.NamedTuple is a subclass of tuple
  • Actual named tuple objects will be an instance of a transient heap type DerivedNamedTuple (subclass of edgedb.NamedTuple)
  • weakref.ref() will stop working on edgedb.NamedTuple objects.
• edgedb.Set is list
• edgedb.Array is list
• edgedb.EnumValue is a subclass of enum.Enum
• link and linkprop? We'll keep them as they are now, and they are not included in the dataclasses.asdict() result.
• docs
• tests

Benchmark:

2.3 GHz Intel 4 Core, Turbo Boost Off, concurrency=10, time=100s

datatypes branch (left):

queries:	184141
qps:		1841 q/s
min latency:	1.88ms
avg latency:	5.42ms
max latency:	28.36ms

0.24 (right):

queries:	188075
qps:		1880 q/s
min latency:	1.37ms
avg latency:	5.30ms
max latency:	88.56ms

Tested query:

    SELECT User {
        id,
        name,
        image,
        enumval := <Color>'Red',
        namedtuple := (a := 1, b := 2.2),
        arr := [1, 2, 3],
        tup := (1, 2, 3),
        latest_reviews := (
            WITH UserReviews := User.<author[IS Review]
            SELECT UserReviews {
                id,
                body,
                rating,
                movie: {
                    id,
                    image,
                    title,
                    avg_rating
                }
            }
            ORDER BY .creation_time DESC
            LIMIT 10
        )
    }
    FILTER .id = <uuid>$id

[i0bs]

edgedb-python/edgedb/datatypes/array.c

Line 47 in dfb8c8b

EdgeArrayObject *obj = NULL;

Will other types from stdlib such as arrays inherit from builtin?

[fantix]

Will other types from stdlib such as arrays inherit from builtin?

Yes, but array may just be a subclass of tuple because it's immutable.

[i0bs]

Yes, but array may just be a subclass of tuple because it's immutable.

Has it always been immutable? I thought EdgeQL supported mutation to the shape and size of arrays.

[fantix]

Has it always been immutable?

Oh this PR is the edgedb-python construct of arrays only in query results, it was and will be immutable.

[1st1]

Why can't we use the builtin tuple type for our tuples? The __repr__ is basically compatible, so maybe just drop our custom tuple implementation and use the builtin one? It has a freelist optimization.

[fantix]

We cannot reuse the builtin freelist for tuple because the ob_type is not &PyTuple_Type.

[fantix]

Has it always been immutable?

Oh this PR is the edgedb-python construct of arrays only in query results, it was and will be immutable.

UPDATE: we decided to use plain Python list for edgedb.Set and edgedb.Array, so the query results will be partially mutable, but again that's just in user memory.

[i0bs]

UPDATE: we decided to use plain Python list for edgedb.Set and edgedb.Array, so the query results will be partially mutable, but again that's just in user memory.

Does the builtin list object support the same optimisation as before? Does this improve querying perf?

[fantix]

UPDATE: we decided to use plain Python list for edgedb.Set and edgedb.Array, so the query results will be partially mutable, but again that's just in user memory.

Does the builtin list object support the same optimisation as before? Does this improve querying perf?

The main optimization is still here, which is using the C API PyList_SET_ITEM for fast initialization, but we lost the (cached) hashing function, which is not a critical use. Also we lost the freelist of array, which may have slight performance impact when arrays are frequently (re-)allocated. Other than that, query performance should not be affected, I’ll run benchmarks to test it.

[i0bs]

I'd love to hear more about the benchmarks once they're available. This sounds like a great change if memory allocation doesn't prove to be too impactful for builtin inheritance. Great stuff @fantix ❤️

[1st1]

LGTM! (Aside from one little nit, see the new comment)

[fantix]

@i0bs benchmark updated