From f5d845426eb38f0b5641c30d0d3a56c2b6a2b6a0 Mon Sep 17 00:00:00 2001
From: Sergei Petrunia <psergey@askmonty.org>
Date: Wed, 24 Sep 2014 11:56:22 +0400
Subject: [PATCH] Better comments

---
 sql/sql_select.cc | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 9c87ddcc4b4..e7424b4a318 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -24706,6 +24706,11 @@ void JOIN::cache_const_exprs()
    - if there is a ref(const) access, we try to use it, too.
    - quick and ref(const) use different cost formulas, so if both are possible
       we should make a cost-based choice.
+  
+  @param  tab              JOIN_TAB with table access (is NULL for single-table
+                           UPDATE/DELETE)
+  @param  read_time OUT    Cost of reading using quick or ref(const) access.
+
 
   @return 
     true   There was a possible quick or ref access, its cost is in the OUT