Fixes #19568

We were never clearing the `PG::Result` object used to query the types
when the connection is first established. This would lead to a
potentially large amount of memory being retained for the life of the
connection.

Investigating this issue also revealed several low hanging fruit on the
performance of these methods, and the number of allocations has been
reduced by ~90%.

Fixes #19578

[ci skip] Fix an object of `reference`

use correct method in batches test

Return super in ActionController::Parameters.const_missing

The current implementation of ActionController::Parameters.const_missing
returns `ActionController::Parameters.always_permitted_parameters` even
if its `super` returns a constant without raising error. This prevents its
subclass in a autoloading module/class from taking advantage of
autoloading constants.

    class SomeParameters < ActionController::Parameters
      def do_something
        DefinedSomewhere.do_something
      end
    end

In the code above, `DefinedSomewhere` is to be autoloaded with
`Module.const_missing` but `ActionController::Parameters.const_missing`
returns `always_permitted_parameters` instead of the autoloaded
constant.

This pull request fixes the issue respecting `const_missing`'s `super`.

Remove old and not working link. [ci skip]

setup as block run before setup actlually runs so it will fail for our
case

We are promoting too much a feature that will not be widler used.
So for now lets keep just the ArrayInquirer constructor.

Provide friendlier access to request variants

 Improve CHANGELOG for fix for respecting pluralize_table_names [ci skip...

[skip ci] Improve `warn_on_records_fetched` code documentation

- ‘dection’ -> ‘detection’

- ‘exceeds threshold’ -> ‘exceeds the threshold’

- Other minor improvements.

respect `pluralize_table_names` when generate fixture file. fixes #19519

[ci skip] Unify the code comment in ActionView::Renderer#render_template...

Correct doc sentence [ci skip]

[skip ci] Update configuring.md with #18846

Add `config.active_record.warn_on_records_fetched_greater_than` to the
Configuring Rails Guide.

Merges 647eb2cf. The pull request as a
whole is quite large, and I'm reviewing the smaller pieces individually.

Merges 1d8d5a74. The pull request as a
whole is quite large, and I'm reviewing the smaller pieces individually.

Add `config.active_record.warn_on_result_set_size` option

Add missing :html option in determine_template error message.

Conflicts:
	guides/source/4_0_release_notes.md

[skip ci] Minor edits for clarity in the test fixture guide.

* Add conjunction for clarity.
* Add comma between independent clauses: create command, and generation
  of fixtures.

When set to an integer, a warning will be logged whenever a result set
larger than the specified size is returned by a query. Fixes #16463

The warning is outputed a module which is prepended in an initializer,
so there will be no performance impact if
`config.active_record.warn_on_records_fetched_greater_than` is not set.

This obsoletes the ruby based implementations.

The type map was introduced in aafee233, but wasn't properly filled.

This mainly adjusts many locations, that expected strings instead of
integers or boolean.

add_pg_decoders is moved after setup of the StatementPool, because
execute_and_clear could potentially make use of it.

Ruby-pg's default way to serialize values for transmission to the database is to
call #to_s . This however creates a temporary String object for each value.
Setting a class based type map avoids the allocation of this additional String.

The performance benefit is measurable in microbenchmarks, but not with
the overhead of activerecord. However it's free to use and has no drawback.

Documenting remove_column as a reversible migration method