diff --git a/bug_report_templates/test-ransack-scope-and-column-same-name.rb b/bug_report_templates/test-ransack-scope-and-column-same-name.rb
index a8f0334b..27655dd9 100644
--- a/bug_report_templates/test-ransack-scope-and-column-same-name.rb
+++ b/bug_report_templates/test-ransack-scope-and-column-same-name.rb
@@ -39,7 +39,7 @@
 # Display versions.
 message = "Running test case with Ruby #{RUBY_VERSION}, Active Record #{
   ::ActiveRecord::VERSION::STRING}, Arel #{Arel::VERSION} and #{
-  ::ActiveRecord::Base.connection.adapter_name}"
+  ::ActiveRecord::Base.adapter_class::ADAPTER_NAME}"
 line = '=' * message.length
 puts line, message, line
 
diff --git a/bug_report_templates/test-ransacker-arel-present-predicate.rb b/bug_report_templates/test-ransacker-arel-present-predicate.rb
index 690ad1ca..eefad098 100644
--- a/bug_report_templates/test-ransacker-arel-present-predicate.rb
+++ b/bug_report_templates/test-ransacker-arel-present-predicate.rb
@@ -37,7 +37,7 @@
 # Display versions.
 message = "Running test case with Ruby #{RUBY_VERSION}, Active Record #{
   ::ActiveRecord::VERSION::STRING}, Arel #{Arel::VERSION} and #{
-  ::ActiveRecord::Base.connection.adapter_name}"
+  ::ActiveRecord::Base.adapter_class::ADAPTER_NAME}"
 line = '=' * message.length
 puts line, message, line
 
diff --git a/lib/ransack/adapters/active_record/context.rb b/lib/ransack/adapters/active_record/context.rb
index e28fd812..10e315a2 100644
--- a/lib/ransack/adapters/active_record/context.rb
+++ b/lib/ransack/adapters/active_record/context.rb
@@ -15,7 +15,7 @@ def type_for(attr)
           relation     = attr.arel_attribute.relation
           name         = attr.arel_attribute.name.to_s
           table        = relation.respond_to?(:table_name) ? relation.table_name : relation.name
-          schema_cache = self.klass.connection.schema_cache
+          schema_cache = self.klass.connection_pool.schema_cache
           unless schema_cache.send(:data_source_exists?, table)
             raise "No table named #{table} exists."
           end
diff --git a/lib/ransack/constants.rb b/lib/ransack/constants.rb
index 027e87be..809ec322 100644
--- a/lib/ransack/constants.rb
+++ b/lib/ransack/constants.rb
@@ -161,7 +161,7 @@ module Constants
   module_function
     # replace % \ to \% \\
     def escape_wildcards(unescaped)
-      case ActiveRecord::Base.connection.adapter_name
+      case ActiveRecord::Base.adapter_class::ADAPTER_NAME
       when "Mysql2".freeze
         # Necessary for MySQL
         unescaped.to_s.gsub(/([\\%_])/, '\\\\\\1')
diff --git a/lib/ransack/nodes/condition.rb b/lib/ransack/nodes/condition.rb
index 0dc01eb0..77d0ed44 100644
--- a/lib/ransack/nodes/condition.rb
+++ b/lib/ransack/nodes/condition.rb
@@ -257,7 +257,7 @@ def arel_predicate_for_attribute(attr)
       end
 
       def attr_value_for_attribute(attr)
-        return attr.attr if ActiveRecord::Base.connection.adapter_name == "PostgreSQL"
+        return attr.attr if ActiveRecord::Base.adapter_class::ADAPTER_NAME == "PostgreSQL"
 
         predicate.case_insensitive ? attr.attr.lower : attr.attr
       rescue
diff --git a/spec/helpers/ransack_helper.rb b/spec/helpers/ransack_helper.rb
index f80e883c..4fb50fdf 100644
--- a/spec/helpers/ransack_helper.rb
+++ b/spec/helpers/ransack_helper.rb
@@ -1,9 +1,9 @@
 module RansackHelper
   def quote_table_name(table)
-    ActiveRecord::Base.connection.quote_table_name(table)
+    ActiveRecord::Base.lease_connection.quote_table_name(table)
   end
 
   def quote_column_name(column)
-    ActiveRecord::Base.connection.quote_column_name(column)
+    ActiveRecord::Base.lease_connection.quote_column_name(column)
   end
 end
diff --git a/spec/ransack/adapters/active_record/base_spec.rb b/spec/ransack/adapters/active_record/base_spec.rb
index 433db347..f87383d4 100644
--- a/spec/ransack/adapters/active_record/base_spec.rb
+++ b/spec/ransack/adapters/active_record/base_spec.rb
@@ -277,7 +277,7 @@ module ActiveRecord
         describe '#ransacker' do
           # For infix tests
           def self.sane_adapter?
-            case ::ActiveRecord::Base.connection.adapter_name
+            case ::ActiveRecord::Base.adapter_class::ADAPTER_NAME
             when 'SQLite3', 'PostgreSQL'
               true
             else
@@ -379,7 +379,7 @@ def self.sane_adapter?
           context 'searching by underscores' do
             # when escaping is supported right in LIKE expression without adding extra expressions
             def self.simple_escaping?
-              case ::ActiveRecord::Base.connection.adapter_name
+              case ::ActiveRecord::Base.adapter_class::ADAPTER_NAME
                 when 'Mysql2', 'PostgreSQL'
                   true
                 else
diff --git a/spec/ransack/configuration_spec.rb b/spec/ransack/configuration_spec.rb
index 9d232143..2244e18d 100644
--- a/spec/ransack/configuration_spec.rb
+++ b/spec/ransack/configuration_spec.rb
@@ -188,7 +188,7 @@ module Ransack
       end
     end
 
-    it "PG's sort option", if: ::ActiveRecord::Base.connection.adapter_name == "PostgreSQL" do
+    it "PG's sort option", if: ::ActiveRecord::Base.adapter_class::ADAPTER_NAME == "PostgreSQL" do
       default = Ransack.options.clone
 
       Ransack.configure { |c| c.postgres_fields_sort_option = :nulls_first }
diff --git a/spec/ransack/predicate_spec.rb b/spec/ransack/predicate_spec.rb
index cf84e200..3cb2d9a1 100644
--- a/spec/ransack/predicate_spec.rb
+++ b/spec/ransack/predicate_spec.rb
@@ -157,7 +157,7 @@ module Ransack
 
     describe 'cont' do
       it_has_behavior 'wildcard escaping', :name_cont,
-        (case ActiveRecord::Base.connection.adapter_name
+        (case ActiveRecord::Base.adapter_class::ADAPTER_NAME
         when "PostGIS", "PostgreSQL"
           /"people"."name" ILIKE '%\\%\\.\\_\\\\%'/
         when "Mysql2"
@@ -177,7 +177,7 @@ module Ransack
 
     describe 'not_cont' do
       it_has_behavior 'wildcard escaping', :name_not_cont,
-        (case ActiveRecord::Base.connection.adapter_name
+        (case ActiveRecord::Base.adapter_class::ADAPTER_NAME
         when "PostGIS", "PostgreSQL"
           /"people"."name" NOT ILIKE '%\\%\\.\\_\\\\%'/
         when  "Mysql2"
@@ -197,7 +197,7 @@ module Ransack
 
     describe 'i_cont' do
       it_has_behavior 'wildcard escaping', :name_i_cont,
-        (case ActiveRecord::Base.connection.adapter_name
+        (case ActiveRecord::Base.adapter_class::ADAPTER_NAME
         when "PostGIS"
           /LOWER\("people"."name"\) ILIKE '%\\%\\.\\_\\\\%'/
         when "PostgreSQL"
@@ -219,7 +219,7 @@ module Ransack
 
     describe 'not_i_cont' do
       it_has_behavior 'wildcard escaping', :name_not_i_cont,
-        (case ActiveRecord::Base.connection.adapter_name
+        (case ActiveRecord::Base.adapter_class::ADAPTER_NAME
         when "PostGIS"
           /LOWER\("people"."name"\) NOT ILIKE '%\\%\\.\\_\\\\%'/
         when "PostgreSQL"
@@ -324,14 +324,14 @@ module Ransack
         @s.awesome_true = true
         field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
         expect(@s.result.to_sql).to match /#{field} = #{
-          ActiveRecord::Base.connection.quoted_true}/
+          ActiveRecord::Base.lease_connection.quoted_true}/
       end
 
       it 'generates an inequality condition for boolean true' do
         @s.awesome_true = false
         field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
         expect(@s.result.to_sql).to match /#{field} != #{
-          ActiveRecord::Base.connection.quoted_true}/
+          ActiveRecord::Base.lease_connection.quoted_true}/
       end
     end
 
@@ -340,14 +340,14 @@ module Ransack
         @s.awesome_not_true = true
         field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
         expect(@s.result.to_sql).to match /#{field} != #{
-          ActiveRecord::Base.connection.quoted_true}/
+          ActiveRecord::Base.lease_connection.quoted_true}/
       end
 
       it 'generates an equality condition for boolean true' do
         @s.awesome_not_true = false
         field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
         expect(@s.result.to_sql).to match /#{field} = #{
-          ActiveRecord::Base.connection.quoted_true}/
+          ActiveRecord::Base.lease_connection.quoted_true}/
       end
     end
 
@@ -356,14 +356,14 @@ module Ransack
         @s.awesome_false = true
         field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
         expect(@s.result.to_sql).to match /#{field} = #{
-          ActiveRecord::Base.connection.quoted_false}/
+          ActiveRecord::Base.lease_connection.quoted_false}/
       end
 
       it 'generates an inequality condition for boolean false' do
         @s.awesome_false = false
         field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
         expect(@s.result.to_sql).to match /#{field} != #{
-          ActiveRecord::Base.connection.quoted_false}/
+          ActiveRecord::Base.lease_connection.quoted_false}/
       end
     end
 
@@ -372,14 +372,14 @@ module Ransack
         @s.awesome_not_false = true
         field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
         expect(@s.result.to_sql).to match /#{field} != #{
-          ActiveRecord::Base.connection.quoted_false}/
+          ActiveRecord::Base.lease_connection.quoted_false}/
       end
 
       it 'generates an equality condition for boolean false' do
         @s.awesome_not_false = false
         field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
         expect(@s.result.to_sql).to match /#{field} = #{
-          ActiveRecord::Base.connection.quoted_false}/
+          ActiveRecord::Base.lease_connection.quoted_false}/
       end
     end
 
diff --git a/spec/ransack/search_spec.rb b/spec/ransack/search_spec.rb
index 26433199..5a7d5070 100644
--- a/spec/ransack/search_spec.rb
+++ b/spec/ransack/search_spec.rb
@@ -666,7 +666,7 @@ def remove_quotes_and_backticks(str)
         end.to raise_error(Ransack::InvalidSearchError,  "Invalid argument (Integer) supplied to sorts=")
       end
 
-      it "PG's sort option", if: ::ActiveRecord::Base.connection.adapter_name == "PostgreSQL" do
+      it "PG's sort option", if: ::ActiveRecord::Base.adapter_class::ADAPTER_NAME == "PostgreSQL" do
         default = Ransack.options.clone
 
         s = Search.new(Person, s: 'name asc')
@@ -687,7 +687,7 @@ def remove_quotes_and_backticks(str)
         Ransack.options = default
       end
 
-      it "PG's sort option with double name", if: ::ActiveRecord::Base.connection.adapter_name == "PostgreSQL" do
+      it "PG's sort option with double name", if: ::ActiveRecord::Base.adapter_class::ADAPTER_NAME == "PostgreSQL" do
         default = Ransack.options.clone
 
         s = Search.new(Person, s: 'doubled_name asc')
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 18facc43..6c93f275 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -35,7 +35,7 @@
 
   config.before(:suite) do
     message = "Running Ransack specs with #{
-      ActiveRecord::Base.connection.adapter_name
+      ActiveRecord::Base.adapter_class::ADAPTER_NAME
       }, Active Record #{::ActiveRecord::VERSION::STRING}, Arel #{Arel::VERSION
       } and Ruby #{RUBY_VERSION}"
     line = '=' * message.length
diff --git a/spec/support/schema.rb b/spec/support/schema.rb
index 02e5b4a1..66433a47 100644
--- a/spec/support/schema.rb
+++ b/spec/support/schema.rb
@@ -40,6 +40,8 @@
   )
 end
 
+ActiveRecord.permanent_connection_checkout = :disallowed
+
 # This is just a test app with no sensitive data, so we explicitly allowlist all
 # attributes and associations for search. In general, end users should
 # explicitly authorize each model, but this shows a way to configure the
@@ -382,7 +384,7 @@ class OperationHistory < Base
   module Schema
     def self.create
       s = ::ActiveRecord::Schema.new
-      s.instance_variable_set(:@connection, SubDB::Base.connection)
+      s.instance_variable_set(:@connection, SubDB::Base.lease_connection)
       s.verbose = false
       s.define({}) do
         create_table :operation_histories, force: true do |t|