Performance degradation when using `field_name_type` with `Symbol.alias_method(:to_s, :name)`

[p8]

I maintain the Ruby frameworks on the https://www.http-arena.com/ benchmarks.

For the Roda tests I've set field_name_type = :symbol to get a 10% performance increase for RPS for the database test (async-db).

After reading https://bugs.ruby-lang.org/issues/22137, I changed the Roda test to let Symbol#to_s return a frozen string by using:

Symbol.alias_method(:to_s, :name)

This resulted in a 57% performance decrease for RPS, for the database test.
I didn't expect this change to have a large impact the database calls.

Reverting the field_name_type = :symbol change resulted in a 108% performance increase for RPS.
This was even more unexpected.

I'm not sure if this is just a issue with the HttpArena tests or a known issue, but I found it interesting enough to share.
Feel free to close this is issue if this isn't something that can or should be fixed.

[larskanis]

The only change for years to this code was #691 which is on master now, but not in pg-1.6.3.

Test	Conn	RPS	CPU	Mem	Δ RPS	Δ Mem
symbol MDA2AV/HttpArena#782	1024	117,100	6322.4%	2.5GiB	+8.6%	~0%
string MDA2AV/HttpArena#996	1024	100,537	6095.8%	2.5GiB	+118.3%	+13.6%
frozen symbol MDA2AV/HttpArena#987	1024	46,052	3273.3%	2.2GiB	-57.3%	-12.0%

Given the absolute numbers (RPS) the difference between symbol (117,100) and string (100,537) seems to be roughly 10%. I don't know why the frozen symbol version is so slow, but I guess it's not in ruby-pg.