Perf: fields in pg gem causes an allocation, cache it

1 files changed, 3 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb
index 751655e61c..527d13b9b0 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb
@@ -139,7 +139,8 @@ module ActiveRecord
                                     exec_cache(sql, binds)
 
             types = {}
-            result.fields.each_with_index do |fname, i|
+            fields = result.fields
+            fields.each_with_index do |fname, i|
               ftype = result.ftype i
               fmod  = result.fmod i
               types[fname] = OID::TYPE_MAP.fetch(ftype, fmod) { |oid, mod|
@@ -148,7 +149,7 @@ module ActiveRecord
               }
             end
 
-            ret = ActiveRecord::Result.new(result.fields, result.values, types)
+            ret = ActiveRecord::Result.new(fields, result.values, types)
             result.clear
             return ret
           end