refactor(storage): use dynamic trait for storage interfaces

[wangrunji0408]

Signed-off-by: Runji Wang [email protected]

Dynamic async traits are not so bad for performance, as long as they are not called frequently. The advantage is that they are less invasive as they do not require generic parameters everywhere, and they allow for extensible plugins in the future.

This PR uses #[async_trait] to refactor storage traits into dyn traits. It removes <S: Storage> from executors. The only performance critical part is the TxnIterator::next_batch which is called frequently in scanning. We refactor it into a BoxStream to eliminate boxing the future on each call.

Performance comparison on TPCH

tpch	time
q1	+5.9%
q17	+5.6%
q18	+5.4%
q13	+4.1%
q11	+3.9%
q14	+3.9%
q7	+3.7%
q4	+3.2%
q3	+3.1%
q10	+2.2%
q9	+1.8%
q5	+1.4%
q15	+1.2%
q16	+1.2%
q19	+1.2%
q6	+0.4%
q12	-0.4%
q20	-0.6%
q22	-2.5%
q2	-2.9%
q8	-2.9%
q21	-5.4%

[TennyZhuang]

Weakly -1

The current dynamic traits have too many limitations, making them seem like unfinished products.

And pass generic parameters are not really very painful.

[wangrunji0408]

also objected by @MrCroxx

[MrCroxx]

also objected by @MrCroxx

The #[async_trait] allocates a boxed future on each call. The overhead can be high for memory-only path. e.g. cache hits.