[MCC-833873] Fix single pg call for accessible_objects from replica

[kjerinsky-mdsol]

PostgreSQL has restrictions on creating temporary tables on replica databases. Adding in the CTE that was used in previous benchmark investigations for use when the database connection a replica.

Benchmarks for 50k user

Single run

method version	user	system	total	real	faster
no pluck	3.163534	0.151665	3.315199	3.845629
pluck	1.610845	0.035368	1.646213	2.271648	40.1%
pg function	0.020938	0.012064	0.033002	0.452649	88.2%
cte	0.041312	0.007820	0.049132	0.624768	83.8%

Multiple runs (5)

method version	user	system	total	real	faster
no pluck	17.658298	0.479222	18.137520	21.150227
pluck	7.143887	0.198251	7.342138	10.431428	50.7%
pg function	0.182273	0.055765	0.238038	2.381902	88.7%
cte	0.163428	0.039802	0.203230	3.082762	85.4%

[cmcinnes-mdsol]

@kjerinsky-mdsol we also need to fix the loading issue that leads to rake tasks failing and containers failing when they first spin up

[cmcinnes-mdsol]

why the bump? asking cause im wondering if this is indeed a development dependency or actually a runtime dependency

[kjerinsky-mdsol]

Because ActiveRecord::Base.connection_db_config.config is logging from Rails 6.1

DEPRECATION WARNING: DatabaseConfig#config will be removed in 6.2.0 in favor of DatabaseConfigurations#configuration_hash which returns a hash with symbol keys (called from irb_binding at (irb):20)

Rails 6.0 doesn't have DatabaseConfigurations#configuration_hash so either get ahead of it or let it potentially sneak up on us.

[kjerinsky-mdsol]

That or check for either method.

[ejinotti-mdsol]

See my other comment

[ejinotti-mdsol]

Also, this is mainly for the test Rails app that is created for running specs I think. If we really cared about this gem we would make it use appraisals for various Ruby/Rails combinations... but, to me, just using the same version as Dalto is fine.

[ejinotti-mdsol]

See my other comment

[ejinotti-mdsol]

There is already a function for doing some ridiculous rigmarole to handle the ever-changing ActiveRecord API surface for getting a DB config:

the_policy_machine/lib/policy_machine_storage_adapters/active_record.rb

Lines 39 to 69 in 6ff77d1

	def self.db_config
	return @_db_config if @_db_config
	ar_configs = PolicyElement.configurations
	# ActiveRecord < 6.0
	unless ar_configs.respond_to?(:configs_for)
	@_db_config = ar_configs[Rails.env].symbolize_keys
	return @_db_config
	end
	config = begin
	# ActiveRecord >= 6.1:
	# there is a deprecation warning for using kwarg 'spec_name'
	# so try the new 'name' kwarg first
	ar_configs.configs_for(env_name: Rails.env, name: 'primary')
	rescue ArgumentError
	# ActiveRecord == 6.0:
	# the kwarg is called 'spec_name'
	ar_configs.configs_for(env_name: Rails.env, spec_name: 'primary')
	end
	@_db_config =
	# AR 6.1 also emits a warning that `.config` is deprecated
	# and `.configuration_hash` is The New Way
	if config.respond_to?(:configuration_hash)
	config.configuration_hash
	else
	config.config.symbolize_keys
	end
	end

Should probably use it somehow.

[ejinotti-mdsol]

Also, this is mainly for the test Rails app that is created for running specs I think. If we really cared about this gem we would make it use appraisals for various Ruby/Rails combinations... but, to me, just using the same version as Dalto is fine.