Clarify DatabaseStatements#execute docs re: memory usage.

2 files changed, 7 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
index 7a2a1a0e33..7e0c9f7837 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
@@ -69,7 +69,11 @@ module ActiveRecord
       end
       undef_method :select_rows
 
-      # Executes the SQL statement in the context of this connection.
+      # Executes the SQL statement in the context of this connection and returns
+      # the raw result from the connection adapter.
+      # Note: depending on your database connector, the result returned by this
+      # method may be manually memory managed. Consider using the exec_query
+      # wrapper instead.
       def execute(sql, name = nil)
       end
       undef_method :execute
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 6c15facf3b..8c7cfae7c1 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb
@@ -128,6 +128,8 @@ module ActiveRecord
 
         # Executes an SQL statement, returning a PGresult object on success
         # or raising a PGError exception otherwise.
+        # Note: the PGresult object is manually memory managed; if you don't
+        # need it specifically, you many want consider the exec_query wrapper.
         def execute(sql, name = nil)
           log(sql, name) do
             @connection.async_exec(sql)