Merge pull request rails#50475 from waymondo/postgres-partition-options

support dumping PostgreSQL inheritance & partitioning options to `schema.rb`

Author: rafaelfranca

activerecord/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Add support for dumping table inheritance and native partitioning table definitions for PostgeSQL adapter
+
+    *Justin Talbott*
+
 *   Deserialize database values before decryption
 
     PostgreSQL binary values (`ActiveRecord::ConnectionAdapters::PostgreSQL::OID::Bytea`)

activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb

@@ -152,9 +152,23 @@ def indexes(table_name) # :nodoc:
         end
 
         def table_options(table_name) # :nodoc:
-          if comment = table_comment(table_name)
-            { comment: comment }
+          options = {}
+
+          comment = table_comment(table_name)
+
+          options[:comment] = comment if comment
+
+          inherited_table_names = inherited_table_names(table_name).presence
+
+          options[:options] = "INHERITS (#{inherited_table_names.join(", ")})" if inherited_table_names
+
+          if !options[:options] && supports_native_partitioning?
+            partition_definition = table_partition_definition(table_name)
+
+            options[:options] = "PARTITION BY #{partition_definition}" if partition_definition
           end
+
+          options
         end
 
         # Returns a comment stored in database for given table
@@ -172,6 +186,36 @@ def table_comment(table_name) # :nodoc:
           end
         end
 
+        # Returns the partition definition of a given table
+        def table_partition_definition(table_name) # :nodoc:
+          scope = quoted_scope(table_name, type: "BASE TABLE")
+
+          query_value(<<~SQL, "SCHEMA")
+            SELECT pg_catalog.pg_get_partkeydef(c.oid)
+            FROM pg_catalog.pg_class c
+              LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
+            WHERE c.relname = #{scope[:name]}
+              AND c.relkind IN (#{scope[:type]})
+              AND n.nspname = #{scope[:schema]}
+          SQL
+        end
+
+        # Returns the inherited table name of a given table
+        def inherited_table_names(table_name) # :nodoc:
+          scope = quoted_scope(table_name, type: "BASE TABLE")
+
+          query_values(<<~SQL, "SCHEMA")
+            SELECT parent.relname
+            FROM pg_catalog.pg_inherits i
+              JOIN pg_catalog.pg_class child ON i.inhrelid = child.oid
+              JOIN pg_catalog.pg_class parent ON i.inhparent = parent.oid
+              LEFT JOIN pg_namespace n ON n.oid = child.relnamespace
+            WHERE child.relname = #{scope[:name]}
+              AND child.relkind IN (#{scope[:type]})
+              AND n.nspname = #{scope[:schema]}
+          SQL
+        end
+
         # Returns the current database name.
         def current_database
           query_value("SELECT current_database()", "SCHEMA")

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -284,6 +284,10 @@ def supports_nulls_not_distinct?
         database_version >= 15_00_00 # >= 15.0
       end
 
+      def supports_native_partitioning? # :nodoc:
+        database_version >= 10_00_00 # >= 10.0
+      end
+
       def index_algorithms
         { concurrently: "CONCURRENTLY" }
       end

activerecord/test/cases/adapters/postgresql/schema_test.rb

@@ -861,3 +861,90 @@ def test_nulls_not_set_is_dumped
     assert_no_match(/nulls_not_distinct/, output)
   end
 end
+
+class SchemaCreateTableOptionsTest < ActiveRecord::PostgreSQLTestCase
+  include SchemaDumpingHelper
+
+  setup do
+    @connection = ActiveRecord::Base.connection
+  end
+
+  teardown do
+    @connection.drop_table "trains", if_exists: true
+    @connection.drop_table "transportation_modes", if_exists: true
+    @connection.drop_table "vehicles", if_exists: true
+  end
+
+  def test_list_partition_options_is_dumped
+    skip("current adapter doesn't support native partitioning") unless supports_native_partitioning?
+
+    options = "PARTITION BY LIST (kind)"
+
+    @connection.create_table "trains", id: false, options: options do |t|
+      t.string :name
+      t.string :kind
+    end
+
+    output = dump_table_schema "trains"
+
+    assert_match("options: \"#{options}\"", output)
+  end
+
+  def test_range_partition_options_is_dumped
+    skip("current adapter doesn't support native partitioning") unless supports_native_partitioning?
+
+    options = "PARTITION BY RANGE (created_at)"
+
+    @connection.create_table "trains", id: false, options: options do |t|
+      t.string :name
+      t.datetime :created_at, null: false
+    end
+
+    output = dump_table_schema "trains"
+
+    assert_match("options: \"#{options}\"", output)
+  end
+
+  def test_inherited_table_options_is_dumped
+    @connection.create_table "transportation_modes" do |t|
+      t.string :name
+      t.string :kind
+    end
+
+    options = "INHERITS (transportation_modes)"
+
+    @connection.create_table "trains", options: options
+
+    output = dump_table_schema "trains"
+
+    assert_match("options: \"#{options}\"", output)
+  end
+
+  def test_multiple_inherited_table_options_is_dumped
+    @connection.create_table "vehicles" do |t|
+      t.string :name
+    end
+
+    @connection.create_table "transportation_modes" do |t|
+      t.string :kind
+    end
+
+    options = "INHERITS (transportation_modes, vehicles)"
+
+    @connection.create_table "trains", options: options
+
+    output = dump_table_schema "trains"
+
+    assert_match("options: \"#{options}\"", output)
+  end
+
+  def test_no_partition_options_are_dumped
+    @connection.create_table "trains" do |t|
+      t.string :name
+    end
+
+    output = dump_table_schema "trains"
+
+    assert_no_match("options:", output)
+  end
+end

activerecord/test/support/adapter_helper.rb

@@ -60,6 +60,7 @@ def supports_text_column_with_default?
     supports_nulls_not_distinct?
     supports_identity_columns?
     supports_virtual_columns?
+    supports_native_partitioning?
   ].each do |method_name|
     define_method method_name do
       ActiveRecord::Base.lease_connection.public_send(method_name)