PostgreSQL, Add input type casts for primitive types.

Ruby-pg's default way to serialize values for transmission to the database is to
call #to_s . This however creates a temporary String object for each value.
Setting a class based type map avoids the allocation of this additional String.

The performance benefit is measurable in microbenchmarks, but not with
the overhead of activerecord. However it's free to use and has no drawback.

1 files changed, 10 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 37bf4d77f8..5a304e6ec5 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -278,6 +278,7 @@ module ActiveRecord
         @table_alias_length = nil
 
         connect
+        add_pg_encoders
         @statements = StatementPool.new @connection,
                                         self.class.type_cast_config_to_integer(config.fetch(:statement_limit) { 1000 })
 
@@ -803,6 +804,15 @@ module ActiveRecord
           end
         end
 
+        def add_pg_encoders
+          map = PG::TypeMapByClass.new
+          map[Integer] = PG::TextEncoder::Integer.new
+          map[TrueClass] = PG::TextEncoder::Boolean.new
+          map[FalseClass] = PG::TextEncoder::Boolean.new
+          map[Float] = PG::TextEncoder::Float.new
+          @connection.type_map_for_queries = map
+        end
+
         def add_pg_decoders
           coders_by_name = {
             'int2' => PG::TextDecoder::Integer,