From: "nobu (Nobuyoshi Nakada)" Date: 2013-11-24T09:01:18+09:00 Subject: [ruby-core:58542] [ruby-trunk - Feature #9143] Optimize CSV to share hash key objects between rows Issue #9143 has been updated by nobu (Nobuyoshi Nakada). assert_predicate(string_key, :frozen?) will show better message when it fails. ---------------------------------------- Feature #9143: Optimize CSV to share hash key objects between rows https://bugs.ruby-lang.org/issues/9143#change-43123 Author: avit (Andrew Vit) Status: Open Priority: Normal Assignee: Category: lib Target version: Currently, when CSV headers are strings, then each row receives a copy of the strings for hash keys. This patch is an optimization to share the same frozen string keys between all rows. Please verify: in the implementation of `Hash::[]`, are strings the only object that is dup'd, or should other types be frozen so they aren't copied for each row too? -- http://bugs.ruby-lang.org/