[Commits] Rev 3761: Added comments in file:///home/psergey/dev2/10.0-mdev83/

Sergey Petrunya psergey at askmonty.org
Tue Dec 31 12:43:21 EET 2013


At file:///home/psergey/dev2/10.0-mdev83/

------------------------------------------------------------
revno: 3761
revision-id: psergey at askmonty.org-20131231104319-oic7jmrqubkx31aj
parent: psergey at askmonty.org-20131230210304-pgvu81vkuaf6dqia
committer: Sergey Petrunya <psergey at askmonty.org>
branch nick: 10.0-mdev83
timestamp: Tue 2013-12-31 14:43:19 +0400
message:
  Added comments
=== modified file 'sql/sql_select.cc'
--- a/sql/sql_select.cc	2013-12-30 21:03:04 +0000
+++ b/sql/sql_select.cc	2013-12-31 10:43:19 +0000
@@ -24540,6 +24540,16 @@ void JOIN::collect_expensive_conjuncts()
 /**
   Compute the added cost of all expensive subqueries if they are pushed
   to their respective optimal positions in a complete join plan.
+  
+  @param idx_start  The first table in the join prefix.
+                    psergey-todo: why are there exist cases where idx_start!=0 ?
+                    For this function idx_start!=0 means "dont put conditions
+                    to the left of idx_start".  This is stupid - this function 
+                    processes ALL conditions in the WHERE clause. What if some
+                    of them are "naturally" attached to a point that is to the
+                    left of idx_start?
+
+  @param idx_end    Last table in the join prefix.
 
   @note
   During join optimization we don't do yet condition pushdown. The WHERE



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