rails/rails — pull request #14790 by krisselden (2014-04-17 21:49:24+00:00)
Title: Optimize select_value, select_values, select_rows in Postgresql adapter.

Reduces creating unused objects in select_value, select_values, and select_rows. The most dramatic reduction is in select_values which used to map(&:first) an array of single element arrays.

Dry up checking whether to exec with cache for and clear the result.