Support to recursively create partitioned index

README.md

@@ -209,21 +209,24 @@ Add an index to a natively partitioned table concurrently, as described in the [
 safe_add_concurrent_partitioned_index :partitioned_table, :column
 ```
 
-Add a composite index using the `hash` index type with custom name suffix.
+Add a composite index using the `hash` index type with custom name for the parent index when the parent table contains sub-partitions.
 
 ```ruby
-# Assuming this table has partitions child1 and child2, the following indexes will be created:
+# Assuming this table has partitions child1 and child2, and child1 has sub-partitions sub1 and sub2,
+# the following indexes will be created:
 #   - custom_name_idx
 #   - index_child1_on_column1_column2 (attached to custom_name_idx)
+#   - index_sub1_on_column1_column2 (attached to index_child1_on_column1_column2)
+#   - index_sub2_on_column1_column2 (attached to index_child1_on_column1_column2)
 #   - index_child2_on_column1_column2 (attached to custom_name_idx)
 safe_add_concurrent_partitioned_index :partitioned_table, [:column1, :column2], name: "custom_name_idx", using: :hash
 ```
 
-Notes:
+Note:
 
-- This method does not support sub-partitioning.
-- This method runs multiple DDL statements non-transactionally.
-  - Creating or attaching an index on a child table could fail. In such cases an exception will be raised, and an `INVALID` index will be left on the parent table.
+This method runs multiple DDL statements non-transactionally.
+Creating or attaching an index on a child table could fail.
+In such cases an exception will be raised, and an `INVALID` index will be left on the parent table.
 
 #### safe\_add\_unvalidated\_check\_constraint
 

lib/pg_ha_migrations/relation.rb

@@ -59,7 +59,9 @@ def self.from_table_name(table, mode=nil)
     end
 
     def natively_partitioned?
-      !!connection.select_value(<<~SQL)
+      return @natively_partitioned if defined?(@natively_partitioned)
+
+      @natively_partitioned = !!connection.select_value(<<~SQL)
         SELECT true
         FROM pg_partitioned_table, pg_class, pg_namespace
         WHERE pg_class.oid = pg_partitioned_table.partrelid
@@ -79,6 +81,7 @@ def partitions(include_sub_partitions: false, include_self: false)
           JOIN pg_namespace child_ns  ON child.relnamespace = child_ns.oid
         WHERE parent.relname = #{connection.quote(name)}
           AND parent_ns.nspname = #{connection.quote(schema)}
+        ORDER BY child.oid -- Ensure consistent ordering for tests
       SQL
 
       if include_sub_partitions

lib/pg_ha_migrations/safe_statements.rb

@@ -199,8 +199,6 @@ def safe_add_concurrent_partitioned_index(
     return if if_not_exists && parent_index.valid?
 
     child_indexes = parent_table.partitions.map do |child_table|
-      raise PgHaMigrations::InvalidMigrationError, "Partitioned table #{parent_table.inspect} contains sub-partitions" if child_table.natively_partitioned?
-
       PgHaMigrations::Index.from_table_and_columns(child_table, columns)
     end
 
@@ -221,8 +219,14 @@ def safe_add_concurrent_partitioned_index(
     end
 
     child_indexes.each do |child_index|
-      # CREATE INDEX CONCURRENTLY ON child_table
-      safe_add_concurrent_index(
+      add_index_method = if child_index.table.natively_partitioned?
+        :safe_add_concurrent_partitioned_index
+      else
+        :safe_add_concurrent_index
+      end
+
+      send(
+        add_index_method,
         child_index.table.fully_qualified_name,
         columns,
         name: child_index.name,
@@ -491,7 +495,6 @@ def _fully_qualified_table_name_for_partman(table)
     end.join(".")
   end
 
-
   def _per_migration_caller
     @_per_migration_caller ||= Kernel.caller
   end