Before IN clause optimization 70ddb8a, Active Record had generated an
SQL with binds when `prepared_statements: true`:
```ruby
# prepared_statements: true
#
# SELECT `authors`.* FROM `authors` WHERE `authors`.`id` IN (?, ?, ?)
#
# prepared_statements: false
#
# SELECT `authors`.* FROM `authors` WHERE `authors`.`id` IN (1, 2, 3)
#
Author.where(id: [1, 2, 3]).to_a
```
But now, binds in IN clause is substituted regardless of whether
`prepared_statements: true` or not:
```ruby
# prepared_statements: true
#
# SELECT `authors`.* FROM `authors` WHERE `authors`.`id`IN (1,2,3)
#
# prepared_statements: false
#
# SELECT `authors`.* FROM `authors` WHERE `authors`.`id`IN (1,2,3)
#
Author.where(id: [1, 2, 3]).to_a
```
I suppose that is considered as a regression for the context:
> While I would prefer that we fix/avoid the too-many-parameters
problem, but I don't like the idea of globally ditching bind params for
this edge case... we're getting to the point where I'd almost consider
anything that doesn't use a bind to be a bug.
https://github.com/rails/rails/pull/33844#issuecomment-421000003
This makes binds consider whether `prepared_statements: true` or not
(i.e. restore the original behavior as before), but still gain that
optimization when need the substitute binds (`prepared_statements: false`,
`relation.to_sql`). Even when `prepared_statements: true`, it still
much faster than before by optimized (bind node less) binds generation.
```ruby
class Post < ActiveRecord::Base
end
ids = (1..1000).each.map do |n|
Post.create!.id
end
puts "prepared_statements: #{Post.connection.prepared_statements.inspect}"
Benchmark.ips do |x|
x.report("where with ids") do
Post.where(id: ids).to_a
end
end
```
* Before (200058b011)
`prepared_statements: true`:
```
Warming up --------------------------------------
where with ids 6.000 i/100ms
Calculating -------------------------------------
where with ids 63.806 (± 7.8%) i/s - 318.000 in 5.015903s
```
`prepared_statements: false`:
```
Warming up --------------------------------------
where with ids 7.000 i/100ms
Calculating -------------------------------------
where with ids 73.550 (± 8.2%) i/s - 371.000 in 5.085672s
```
* Now with this change
`prepared_statements: true`:
```
Warming up --------------------------------------
where with ids 9.000 i/100ms
Calculating -------------------------------------
where with ids 91.992 (± 7.6%) i/s - 459.000 in 5.020817s
```
`prepared_statements: false`:
```
Warming up --------------------------------------
where with ids 10.000 i/100ms
Calculating -------------------------------------
where with ids 104.335 (± 8.6%) i/s - 520.000 in 5.026425s
```
157f6a6efe