Export the random generation code as a virtual table in sqlite3

[NobodyXu]

Signed-off-by: Jiahao XU Jiahao_XU@outlook.com

[NobodyXu]

Here's (part of) the benchmark result on my i7-8750H:

Sat Jul 24 21:39:03 AEST 2021 [RUST] basic.rs (100_000_000) inserts

real	3m12.667s
user	3m10.232s
sys	0m1.746s

Sat Jul 24 21:42:16 AEST 2021 [RUST] basic_batched_wp.rs (100_000_000) inserts

real	2m26.269s
user	2m24.799s
sys	0m1.470s

Sat Jul 24 21:44:43 AEST 2021 [RUST] threaded_str_batched.rs (100_000_000) inserts

real	2m17.571s
user	2m32.413s
sys	0m2.181s

Sat Jul 24 21:47:01 AEST 2021 [RUST] basic_prep.rs (100_000_000) inserts

real	0m59.657s
user	0m58.895s
sys	0m0.760s

Sat Jul 24 21:48:02 AEST 2021 [RUST] basic_batched.rs (100_000_000) inserts

real	0m24.746s
user	0m23.856s
sys	0m0.890s

Sat Jul 24 21:48:27 AEST 2021 [RUST] threaded_batched.rs (100_000_000) inserts

real	0m25.210s
user	0m33.036s
sys	0m5.265s

Sat Jul 24 21:48:53 AEST 2021 [RUST] vtable.rs (100_000_000) inserts

real	0m23.487s
user	0m23.077s
sys	0m0.410s

[NobodyXu]

I've requested a PR rusqlite/rusqlite#999 to rusqlite to enable LTO support when using clang-like compiler and using feature "bundled" in libsqlite-sys, which might also improve performance of the vtable.rs.

[avinassh]

Hey! Thanks for the PR. I ran the code, I don't see much difference 🤔

Mon Jul 26 19:41:26 IST 2021 [RUST] threaded_batched.rs (100_000_000) inserts

real	0m34.875s
user	0m46.887s
sys	0m4.503s

Mon Jul 26 19:42:03 IST 2021 [RUST] vtable.rs (100_000_000) inserts

real	0m34.244s
user	0m29.748s
sys	0m2.527s

I added SQLite optimisations, ran again. It did not make much difference either:

Mon Jul 26 19:42:03 IST 2021 [RUST] vtable.rs (100_000_000) inserts

real	0m34.818s
user	0m29.118s
sys	0m2.768s

[NobodyXu]

While it’s true that the “real” execution time of vtable isn’t faster, it takes less sys time and also uses only one thread, which mean it uses less resource to accomplish the same task.

On the up side, I am preparing a PR for statically linking sqlite3 with LTO enabled, after that PR, vtable might run faster.