File 0738-Document-performance-reduction-with-QLC-st... of Package erlang

Overview Repositories Revisions Requests Users Attributes Meta

File 0738-Document-performance-reduction-with-QLC-string-handl.patch of Package erlang (Revision 5fabdb99534eebfde997df7f0642f69a)

Currently displaying revision 5fabdb99534eebfde997df7f0642f69a , Show latest

From 3d8aa06ece2a844d08ae0ea16378d609c0b7c04b Mon Sep 17 00:00:00 2001
From: Johannes Christ <jc@jchri.st>
Date: Mon, 22 May 2023 20:24:42 +0200
Subject: [PATCH] Document performance reduction with QLC string handles

`qlc:string_to_handle` seems to have worse performance than `qlc:q` with
the same input query, presumably because the parse transform is not
optimizing `qlc:string_to_handle`.

Benchmarks that showcase this behaviour can be found here:
https://elixirforum.com/t/performance-discrepancies-with-using-qlc-queries-written-in-erlang-and-elixir/
---
 lib/stdlib/doc/src/qlc.xml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lib/stdlib/doc/src/qlc.xml b/lib/stdlib/doc/src/qlc.xml
index 18f2bcfb10..84302337fa 100644
--- a/lib/stdlib/doc/src/qlc.xml
+++ b/lib/stdlib/doc/src/qlc.xml
@@ -1247,6 +1247,11 @@ ets:match_spec_run(
 <anno>Options</anno>, erl_eval:new_bindings())</c>.
 This function is probably mainly useful when called from
 outside of Erlang, for example from a driver written in C.
+ <note>
+ Query handles created this way may have worse
+ performance than when created directly via
+ <seemfa marker="#q/1"><c>q/1,2</c></seemfa>.
+ </note>
 </desc>
 </func>
 
-- 
2.35.3

Places

File 0738-Document-performance-reduction-with-QLC-string-handl.patch of Package erlang (Revision 5fabdb99534eebfde997df7f0642f69a)

Places