Bump the minimum version of PostgreSQL to 9.3

https://www.postgresql.org/support/versioning/

- 9.1 EOLed on September 2016.
- 9.2 EOLed on September 2017.

9.3 is also not supported since Nov 8, 2018.  https://www.postgresql.org/about/news/1905/
I think it may be a little bit early to drop PostgreSQL 9.3 yet.

* Deprecated `supports_ranges?` since no other databases support range data type

* Add `supports_materialized_views?` to abstract adapter
Materialized views itself is supported by other databases, other connection adapters may support them

* Remove `with_manual_interventions`
It was only necessary for PostgreSQL 9.1 or earlier

* Drop CI against PostgreSQL 9.2

1 files changed, 12 insertions, 19 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 1cef8339f5..1c4e625ead 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -185,7 +185,7 @@ module ActiveRecord
       end
 
       def supports_json?
-        postgresql_version >= 90200
+        true
       end
 
       def supports_comments?
@@ -332,16 +332,16 @@ module ActiveRecord
       end
 
       def supports_ranges?
-        # Range datatypes weren't introduced until PostgreSQL 9.2
-        postgresql_version >= 90200
+        true
       end
+      deprecate :supports_ranges?
 
       def supports_materialized_views?
-        postgresql_version >= 90300
+        true
       end
 
       def supports_foreign_tables?
-        postgresql_version >= 90300
+        true
       end
 
       def supports_pgcrypto_uuid?
@@ -425,8 +425,8 @@ module ActiveRecord
 
       private
         def check_version
-          if postgresql_version < 90100
-            raise "Your version of PostgreSQL (#{postgresql_version}) is too old. Active Record supports PostgreSQL >= 9.1."
+          if postgresql_version < 90300
+            raise "Your version of PostgreSQL (#{postgresql_version}) is too old. Active Record supports PostgreSQL >= 9.3."
           end
         end
 
@@ -589,18 +589,11 @@ module ActiveRecord
         def load_additional_types(oids = nil)
           initializer = OID::TypeMapInitializer.new(type_map)
 
-          if supports_ranges?
-            query = <<~SQL
-              SELECT t.oid, t.typname, t.typelem, t.typdelim, t.typinput, r.rngsubtype, t.typtype, t.typbasetype
-              FROM pg_type as t
-              LEFT JOIN pg_range as r ON oid = rngtypid
-            SQL
-          else
-            query = <<~SQL
-              SELECT t.oid, t.typname, t.typelem, t.typdelim, t.typinput, t.typtype, t.typbasetype
-              FROM pg_type as t
-            SQL
-          end
+          query = <<~SQL
+            SELECT t.oid, t.typname, t.typelem, t.typdelim, t.typinput, r.rngsubtype, t.typtype, t.typbasetype
+            FROM pg_type as t
+            LEFT JOIN pg_range as r ON oid = rngtypid
+          SQL
 
           if oids
             query += "WHERE t.oid::integer IN (%s)" % oids.join(", ")