Dumping partial indexes in schema

Author: alno

lib/arjdbc/postgresql/adapter.rb

@@ -1340,15 +1340,24 @@ def indexes(table_name, name = nil)
           WHERE a.attrelid = #{oid}
           AND a.attnum IN (#{indkey.join(",")})
         SQL
-        
+
         columns = Hash[ columns.each { |column| column[0] = column[0].to_s } ]
         column_names = columns.values_at(*indkey).compact
 
-        # add info on sort order for columns (only desc order is explicitly specified, asc is the default)
-        desc_order_columns = inddef.scan(/(\w+) DESC/).flatten
-        orders = desc_order_columns.any? ? Hash[ desc_order_columns.map { |column| [column, :desc] } ] : {}
-        
-        column_names.empty? ? nil : IndexDefinition.new(table_name, index_name, unique, column_names, [], orders)
+        unless column_names.empty?
+          # add info on sort order for columns (only desc order is explicitly specified, asc is the default)
+          desc_order_columns = inddef.scan(/(\w+) DESC/).flatten
+          orders = desc_order_columns.any? ? Hash[ desc_order_columns.map { |column| [column, :desc] } ] : {}
+
+          if ActiveRecord::VERSION::MAJOR > 3 # AR4 supports `where` and `using` index options
+            where = inddef.scan(/WHERE (.+)$/).flatten[0]
+            using = inddef.scan(/USING (.+?) /).flatten[0].to_sym
+
+            IndexDefinition.new(table_name, index_name, unique, column_names, [], orders, where, nil, using)
+          else
+            IndexDefinition.new(table_name, index_name, unique, column_names, [], orders)
+          end
+        end
       end
       result.compact!
       result

test/db/postgres/schema_dump_test.rb

@@ -1,3 +1,4 @@
+# encoding: utf-8
 require 'db/postgres'
 require 'schema_dump'
 
@@ -76,9 +77,15 @@ def test_schema_dump_integer_with_limit_8_should_have_limit_8
     assert ! lines.empty?
     lines.each {|line| assert line =~ /(limit => 8)|(limit: 8)/ }
   end
-  
+
+  def test_schema_dumps_partial_indices
+    index_definition = standard_dump.split(/\n/).grep(/add_index.*thing_partial_index/).first.strip
+
+    assert_equal 'add_index "things", ["created_at"], name: "thing_partial_index", where: "(name IS NOT NULL)", using: :btree', index_definition
+  end if ar_version('4.0')
+
   private
-  
+
   def dump_with_data_types(io = StringIO.new)
     ActiveRecord::SchemaDumper.ignore_tables = [/^[^d]/] # keep data_types
     ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, io)

test/models/thing.rb

@@ -5,6 +5,7 @@ def self.up
       t.timestamps
     end
     add_index :things, :name, :unique => true
+    add_index :things, :created_at, :where => 'name IS NOT NULL', :name => "thing_partial_index"
   end
 
   def self.down