diff --git a/lib/active_record/connection_adapters/sqlserver/core_ext/attribute_methods.rb b/lib/active_record/connection_adapters/sqlserver/core_ext/attribute_methods.rb
index af0e6a4e7..9cf0a7959 100644
--- a/lib/active_record/connection_adapters/sqlserver/core_ext/attribute_methods.rb
+++ b/lib/active_record/connection_adapters/sqlserver/core_ext/attribute_methods.rb
@@ -10,7 +10,7 @@ module AttributeMethods
           private
 
           def attributes_for_update(attribute_names)
-            return super unless self.class.connection.adapter_name == "SQLServer"
+            return super unless self.class.lease_connection.adapter_name == "SQLServer"
 
             super.reject do |name|
               column = self.class.columns_hash[name]
diff --git a/lib/active_record/connection_adapters/sqlserver/core_ext/calculations.rb b/lib/active_record/connection_adapters/sqlserver/core_ext/calculations.rb
index 34355ef53..b35a719e6 100644
--- a/lib/active_record/connection_adapters/sqlserver/core_ext/calculations.rb
+++ b/lib/active_record/connection_adapters/sqlserver/core_ext/calculations.rb
@@ -9,7 +9,7 @@ module SQLServer
       module CoreExt
         module Calculations
           def calculate(operation, column_name)
-            if klass.connection.sqlserver?
+            if klass.lease_connection.sqlserver?
               _calculate(operation, column_name)
             else
               super
@@ -54,7 +54,7 @@ def _calculate(operation, column_name)
           end
 
           def build_count_subquery(relation, column_name, distinct)
-            return super unless klass.connection.adapter_name == "SQLServer"
+            return super unless klass.lease_connection.adapter_name == "SQLServer"
 
             super(relation.unscope(:order), column_name, distinct)
           end
diff --git a/lib/active_record/connection_adapters/sqlserver/core_ext/explain.rb b/lib/active_record/connection_adapters/sqlserver/core_ext/explain.rb
index 4eea43e3d..6f17fa249 100644
--- a/lib/active_record/connection_adapters/sqlserver/core_ext/explain.rb
+++ b/lib/active_record/connection_adapters/sqlserver/core_ext/explain.rb
@@ -9,7 +9,7 @@ module Explain
           SQLSERVER_STATEMENT_REGEXP = /N'(.+)', N'(.+)', (.+)/
 
           def exec_explain(queries, options = [])
-            return super unless connection.adapter_name == "SQLServer"
+            return super unless lease_connection.adapter_name == "SQLServer"
 
             unprepared_queries = queries.map do |(sql, binds)|
               [unprepare_sqlserver_statement(sql, binds), binds]
diff --git a/lib/active_record/connection_adapters/sqlserver/core_ext/finder_methods.rb b/lib/active_record/connection_adapters/sqlserver/core_ext/finder_methods.rb
index fe9271508..86b866078 100644
--- a/lib/active_record/connection_adapters/sqlserver/core_ext/finder_methods.rb
+++ b/lib/active_record/connection_adapters/sqlserver/core_ext/finder_methods.rb
@@ -11,7 +11,7 @@ module FinderMethods
           private
 
           def construct_relation_for_exists(conditions)
-            if klass.connection.sqlserver?
+            if klass.lease_connection.sqlserver?
               _construct_relation_for_exists(conditions)
             else
               super
diff --git a/lib/active_record/connection_adapters/sqlserver_adapter.rb b/lib/active_record/connection_adapters/sqlserver_adapter.rb
index 1e272d913..bffaad63a 100644
--- a/lib/active_record/connection_adapters/sqlserver_adapter.rb
+++ b/lib/active_record/connection_adapters/sqlserver_adapter.rb
@@ -29,12 +29,13 @@
 require "active_record/connection_adapters/sqlserver/table_definition"
 require "active_record/connection_adapters/sqlserver/quoting"
 require "active_record/connection_adapters/sqlserver/utils"
-require "active_record/sqlserver_base"
 require "active_record/connection_adapters/sqlserver_column"
 require "active_record/tasks/sqlserver_database_tasks"
 
 module ActiveRecord
   module ConnectionAdapters
+    register "sqlserver", "ActiveRecord::ConnectionAdapters::SQLServerAdapter", "active_record/connection_adapters/sqlserver_adapter"
+
     class SQLServerAdapter < AbstractAdapter
       include SQLServer::Version,
               SQLServer::Quoting,
diff --git a/lib/active_record/sqlserver_base.rb b/lib/active_record/sqlserver_base.rb
deleted file mode 100644
index 9dbcbc623..000000000
--- a/lib/active_record/sqlserver_base.rb
+++ /dev/null
@@ -1,13 +0,0 @@
-# frozen_string_literal: true
-
-module ActiveRecord
-  module ConnectionHandling
-    def sqlserver_adapter_class
-      ConnectionAdapters::SQLServerAdapter
-    end
-
-    def sqlserver_connection(config) #:nodoc:
-      sqlserver_adapter_class.new(config)
-    end
-  end
-end
diff --git a/test/cases/adapter_test_sqlserver.rb b/test/cases/adapter_test_sqlserver.rb
index 34394732b..f02e9e706 100644
--- a/test/cases/adapter_test_sqlserver.rb
+++ b/test/cases/adapter_test_sqlserver.rb
@@ -508,7 +508,7 @@ class AdapterTestSQLServer < ActiveRecord::TestCase
 
   describe "block writes to a database" do
     def setup
-      @conn = ActiveRecord::Base.connection
+      @conn = ActiveRecord::Base.lease_connection
     end
 
     def test_errors_when_an_insert_query_is_called_while_preventing_writes
diff --git a/test/cases/coerced_tests.rb b/test/cases/coerced_tests.rb
index 315a2ac45..9445bb06b 100644
--- a/test/cases/coerced_tests.rb
+++ b/test/cases/coerced_tests.rb
@@ -197,7 +197,7 @@ class BasicsTest < ActiveRecord::TestCase
   # Use square brackets as SQL Server escaped character
   coerce_tests! :test_column_names_are_escaped
   def test_column_names_are_escaped_coerced
-    conn = ActiveRecord::Base.connection
+    conn = ActiveRecord::Base.lease_connection
     assert_equal "[t]]]", conn.quote_column_name("t]")
   end
 
@@ -236,7 +236,7 @@ def test_update_date_time_attributes_with_default_timezone_local
     ActiveRecord::Base.while_preventing_writes do
       assert_queries(1, ignore_none: true) do
         Bird.transaction do
-          ActiveRecord::Base.connection.materialize_transactions
+          ActiveRecord::Base.lease_connection.materialize_transactions
         end
       end
     end
@@ -1542,9 +1542,9 @@ def test_dump_schema_information_outputs_lexically_reverse_ordered_versions_rega
       @schema_migration.create_version(v)
     end
 
-    schema_info = ActiveRecord::Base.connection.dump_schema_information
+    schema_info = ActiveRecord::Base.lease_connection.dump_schema_information
     expected = <<~STR
-    INSERT INTO #{ActiveRecord::Base.connection.quote_table_name("schema_migrations")} (version) VALUES
+    INSERT INTO #{ActiveRecord::Base.lease_connection.quote_table_name("schema_migrations")} (version) VALUES
     (N'20100301010101'),
     (N'20100201010101'),
     (N'20100101010101');
@@ -1602,7 +1602,7 @@ class SchemaDumperDefaultsCoerceTest < ActiveRecord::TestCase
   include SchemaDumpingHelper
 
   setup do
-    @connection = ActiveRecord::Base.connection
+    @connection = ActiveRecord::Base.lease_connection
     @connection.create_table :dump_defaults, force: true do |t|
       t.string   :string_with_default,   default: "Hello!"
       t.date     :date_with_default,     default: "2014-06-05"
@@ -2213,15 +2213,15 @@ def test_insert_all_coerced
       Task.cache { Task.insert({ starting: Time.now }) }
     end
 
-    assert_called(ActiveRecord::Base.connection, :clear_query_cache, times: 2) do
+    assert_called(ActiveRecord::Base.lease_connection, :clear_query_cache, times: 2) do
       Task.cache { Task.insert_all!([{ starting: Time.now }]) }
     end
 
-    assert_called(ActiveRecord::Base.connection, :clear_query_cache, times: 2) do
+    assert_called(ActiveRecord::Base.lease_connection, :clear_query_cache, times: 2) do
       Task.cache { Task.insert!({ starting: Time.now }) }
     end
 
-    assert_called(ActiveRecord::Base.connection, :clear_query_cache, times: 2) do
+    assert_called(ActiveRecord::Base.lease_connection, :clear_query_cache, times: 2) do
       Task.cache { Task.insert_all!([{ starting: Time.now }]) }
     end
 
@@ -2287,7 +2287,7 @@ class MarshalSerializationTest < ActiveRecord::TestCase
   undef_method :marshal_fixture_path
   def marshal_fixture_path(file_name)
     File.expand_path(
-      "support/marshal_compatibility_fixtures/#{ActiveRecord::Base.connection.adapter_name}/#{file_name}.dump",
+      "support/marshal_compatibility_fixtures/#{ActiveRecord::Base.lease_connection.adapter_name}/#{file_name}.dump",
       ARTest::SQLServer.test_root_sqlserver
     )
   end
@@ -2379,7 +2379,7 @@ class BasePreventWritesTest < ActiveRecord::TestCase
     ActiveRecord::Base.while_preventing_writes do
       assert_queries(1, ignore_none: true) do
         Bird.transaction do
-          ActiveRecord::Base.connection.materialize_transactions
+          ActiveRecord::Base.lease_connection.materialize_transactions
         end
       end
     end
@@ -2489,7 +2489,7 @@ def test_sqlcommenter_format_value_string_coercible_coerced
   def test_invalid_encoding_query_coerced
     ActiveRecord::QueryLogs.tags = [ :application ]
     assert_raises ActiveRecord::StatementInvalid do
-      ActiveRecord::Base.connection.execute "select 1 as '\xFF'"
+      ActiveRecord::Base.lease_connection.execute "select 1 as '\xFF'"
     end
   end
 end
diff --git a/test/cases/disconnected_test_sqlserver.rb b/test/cases/disconnected_test_sqlserver.rb
index 2936cf93f..382ca51b2 100644
--- a/test/cases/disconnected_test_sqlserver.rb
+++ b/test/cases/disconnected_test_sqlserver.rb
@@ -7,7 +7,7 @@ class TestDisconnectedAdapter < ActiveRecord::TestCase
 
   undef_method :setup
   def setup
-    @connection = ActiveRecord::Base.connection
+    @connection = ActiveRecord::Base.lease_connection
   end
 
   teardown do
diff --git a/test/cases/json_test_sqlserver.rb b/test/cases/json_test_sqlserver.rb
index a863868a8..501210a12 100644
--- a/test/cases/json_test_sqlserver.rb
+++ b/test/cases/json_test_sqlserver.rb
@@ -2,7 +2,7 @@
 
 require "cases/helper_sqlserver"
 
-if ActiveRecord::Base.connection.supports_json?
+if ActiveRecord::Base.lease_connection.supports_json?
   class JsonTestSQLServer < ActiveRecord::TestCase
     before do
       @o1 = SSTestDatatypeMigrationJson.create! json_col: { "a" => "a", "b" => "b", "c" => "c" }
diff --git a/test/cases/lateral_test_sqlserver.rb b/test/cases/lateral_test_sqlserver.rb
index 17aea3c9b..fb1660110 100644
--- a/test/cases/lateral_test_sqlserver.rb
+++ b/test/cases/lateral_test_sqlserver.rb
@@ -16,7 +16,7 @@ class LateralTestSQLServer < ActiveRecord::TestCase
     eq = Arel::Nodes::Equality.new(one, one)
 
     sql = author.project(Arel.star).where(author[:name].matches("David")).outer_join(subselect.lateral.as("bar")).on(eq).to_sql
-    results = ActiveRecord::Base.connection.exec_query sql
+    results = ActiveRecord::Base.lease_connection.exec_query sql
     assert_equal sql, "SELECT * FROM [authors] OUTER APPLY (SELECT * FROM [posts] WHERE [posts].[author_id] = [authors].[id] AND [posts].[id] = 42 ORDER BY [posts].[id] ASC OFFSET 0 ROWS FETCH NEXT 1 ROWS ONLY) AS bar WHERE [authors].[name] LIKE N'David'"
     assert_equal results.length, 1
   end
@@ -27,7 +27,7 @@ class LateralTestSQLServer < ActiveRecord::TestCase
     subselect = post.project(Arel.star).take(1).where(post[:author_id].eq(author[:id])).where(post[:id].eq(42))
 
     sql = author.project(Arel.star).where(author[:name].matches("David")).join(subselect.lateral.as("bar")).to_sql
-    results = ActiveRecord::Base.connection.exec_query sql
+    results = ActiveRecord::Base.lease_connection.exec_query sql
 
     assert_equal sql, "SELECT * FROM [authors] CROSS APPLY (SELECT * FROM [posts] WHERE [posts].[author_id] = [authors].[id] AND [posts].[id] = 42 ORDER BY [posts].[id] ASC OFFSET 0 ROWS FETCH NEXT 1 ROWS ONLY) AS bar WHERE [authors].[name] LIKE N'David'"
     assert_equal results.length, 0
diff --git a/test/cases/primary_keys_test_sqlserver.rb b/test/cases/primary_keys_test_sqlserver.rb
index 433c17de0..8edf3dcfe 100644
--- a/test/cases/primary_keys_test_sqlserver.rb
+++ b/test/cases/primary_keys_test_sqlserver.rb
@@ -12,7 +12,7 @@ class Barcode < ActiveRecord::Base
   end
 
   setup do
-    @connection = ActiveRecord::Base.connection
+    @connection = ActiveRecord::Base.lease_connection
     @connection.create_table(:barcodes, primary_key: "code", id: :uuid, force: true)
   end
 
@@ -50,7 +50,7 @@ class Widget < ActiveRecord::Base
   end
 
   setup do
-    @connection = ActiveRecord::Base.connection
+    @connection = ActiveRecord::Base.lease_connection
   end
 
   teardown do
diff --git a/test/cases/schema_dumper_test_sqlserver.rb b/test/cases/schema_dumper_test_sqlserver.rb
index 13ba5b5ce..f6ae6b2c3 100644
--- a/test/cases/schema_dumper_test_sqlserver.rb
+++ b/test/cases/schema_dumper_test_sqlserver.rb
@@ -5,7 +5,7 @@
 class SchemaDumperTestSQLServer < ActiveRecord::TestCase
   before { all_tables }
 
-  let(:all_tables)   { ActiveRecord::Base.connection.tables }
+  let(:all_tables)   { ActiveRecord::Base.lease_connection.tables }
   let(:schema)       { @generated_schema }
 
   it "sst_datatypes" do
@@ -166,7 +166,7 @@ def generate_schema_for_table(*table_names)
 
     stream = StringIO.new
     ActiveRecord::SchemaDumper.ignore_tables = all_tables - table_names
-    ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, stream)
+    ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.lease_connection, stream)
     @generated_schema = stream.string
     yield @generated_schema if block_given?
     @schema_lines = Hash.new
diff --git a/test/cases/specific_schema_test_sqlserver.rb b/test/cases/specific_schema_test_sqlserver.rb
index 6148f0874..c4590ce81 100644
--- a/test/cases/specific_schema_test_sqlserver.rb
+++ b/test/cases/specific_schema_test_sqlserver.rb
@@ -159,14 +159,14 @@ def quoted_id
 
   it "returns a new id via connection newid_function" do
     acceptable_uuid = ActiveRecord::ConnectionAdapters::SQLServer::Type::Uuid::ACCEPTABLE_UUID
-    db_uuid = ActiveRecord::Base.connection.newid_function
+    db_uuid = ActiveRecord::Base.lease_connection.newid_function
     _(db_uuid).must_match(acceptable_uuid)
   end
 
   # with similar table definition in two schemas
 
   it "returns the correct primary columns" do
-    connection = ActiveRecord::Base.connection
+    connection = ActiveRecord::Base.lease_connection
     assert_equal "field_1", connection.columns("test.sst_schema_test_mulitple_schema").detect(&:is_primary?).name
     assert_equal "field_2", connection.columns("test2.sst_schema_test_mulitple_schema").detect(&:is_primary?).name
   end
diff --git a/test/cases/view_test_sqlserver.rb b/test/cases/view_test_sqlserver.rb
index b371bd0b1..73ddf006a 100644
--- a/test/cases/view_test_sqlserver.rb
+++ b/test/cases/view_test_sqlserver.rb
@@ -3,7 +3,7 @@
 require "cases/helper_sqlserver"
 
 class ViewTestSQLServer < ActiveRecord::TestCase
-  let(:connection) { ActiveRecord::Base.connection }
+  let(:connection) { ActiveRecord::Base.lease_connection }
 
   describe 'view with default values' do
     before do
diff --git a/test/support/connection_reflection.rb b/test/support/connection_reflection.rb
index a739f76ee..b7fe15ce2 100644
--- a/test/support/connection_reflection.rb
+++ b/test/support/connection_reflection.rb
@@ -8,7 +8,7 @@ module ConnectionReflection
       included { extend ConnectionReflection }
 
       def connection
-        ActiveRecord::Base.connection
+        ActiveRecord::Base.lease_connection
       end
 
       def connection_options
diff --git a/test/support/test_in_memory_oltp.rb b/test/support/test_in_memory_oltp.rb
index 88c918c92..2b5bb0c19 100644
--- a/test/support/test_in_memory_oltp.rb
+++ b/test/support/test_in_memory_oltp.rb
@@ -8,10 +8,10 @@
 
   ARTest.connect
 
-  if ActiveRecord::Base.connection.supports_in_memory_oltp?
+  if ActiveRecord::Base.lease_connection.supports_in_memory_oltp?
     puts "Configuring In-Memory OLTP..."
     inmem_file = ARTest::SQLServer.test_root_sqlserver, "schema", "enable-in-memory-oltp.sql"
     inmem_sql = File.read File.join(inmem_file)
-    ActiveRecord::Base.connection.execute(inmem_sql)
+    ActiveRecord::Base.lease_connection.execute(inmem_sql)
   end
 end