With commit e24d770 in place, I took a closer look at hex_decode(), and I concluded that doing anything better without intrinsics would likely require either a huge lookup table or something with complexity rivalling the instrinsics approach (while also not rivalling its performance). So, I took a closer look at the instrinsics patches and had the following thoughts:
* The approach looks generally reasonable to me, but IMHO the code needs much more commentary to explain how it works. * The functions that test the length before potentially calling a function pointer should probably be inlined (see pg_popcount() in pg_bitutils.h). I wouldn't be surprised if some compilers are inlining this stuff already, but it's probably worth being explicit about it. * Finally, I think we should ensure we've established a really strong case for this optimization. IME these intrinsics patches require a ton of time and energy, and the code is often extremely complex. I would be interested to see how your bytea test compares with the improvements added in commit e24d770 and with sending the data in binary. -- nathan
