bk commit into 5.0 tree (evgen:1.1974) BUG#13293

[eugene]

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ChangeSet
  1.1974 05/11/10 23:59:35 evgen@stripped +3 -0
  Fix bug#13293 Wrongly used index results in endless loop.
  
  Loose index scan using only second part of multipart index was choosen, which
  results in creating wrong keys and endless loop.
  
  get_best_group_min_max() now checks whether all keyparts from 1 to 
  max keypart used are used.

  mysql-test/t/select.test
    1.91 05/11/10 23:54:37 evgen@stripped +10 -0
    Test case for bug #13293 Wrongly used index results in endless loop.

  mysql-test/r/select.result
    1.111 05/11/10 23:52:52 evgen@stripped +10 -0
    Test case for bug #13293 Wrongly used index results in endless loop.

  sql/opt_range.cc
    1.197 05/11/10 23:51:07 evgen@stripped +9 -0
    Fix bug #13293 Wrongly used index results in endless loop.
    get_best_group_min_max() now allows loose index scan only if all keyparts from 1 to
max keypart used are used.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	evgen
# Host:	moonbone.local
# Root:	/work/13293-bug-5.0-mysql

--- 1.196/sql/opt_range.cc	2005-11-03 17:42:03 +03:00
+++ 1.197/sql/opt_range.cc	2005-11-10 23:51:07 +03:00
@@ -7188,6 +7188,7 @@
     */
     else if (join->select_distinct)
     {
+      ulonglong all_parts, cur_parts;
       select_items_it.rewind();
       cur_used_key_parts.clear_all();
       while ((item= select_items_it++))
@@ -7208,6 +7209,14 @@
         cur_used_key_parts.set_bit(key_part_nr);
         ++cur_group_key_parts;
       }
+      /* Check if all key parts from 1 to max keypart used are used. */
+      all_parts= 1;
+      cur_parts= cur_used_key_parts.to_ulonglong() >> 1;
+      while (all_parts <= cur_parts)
+        all_parts<<= 1;
+      all_parts--;
+      if (all_parts != cur_parts)
+        DBUG_RETURN(NULL);
     }
     else
       DBUG_ASSERT(FALSE);

--- 1.110/mysql-test/r/select.result	2005-11-03 13:55:07 +03:00
+++ 1.111/mysql-test/r/select.result	2005-11-10 23:52:52 +03:00
@@ -3241,3 +3241,13 @@
 Warnings:
 Warning	1292	Incorrect date value: '2005-09-3a' for column 'f2' at row 1
 drop table t1;
+create table t1 (f1 int, f2 char(1), primary key(f1,f2)) engine=innodb;
+insert into t1 values ( 1,"e"),(2,"a"),( 3,"c"),(4,"d");
+alter table t1 drop primary key, add primary key (f2, f1);
+explain select distinct f1 a, f1 b from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	PRIMARY	5	NULL	4	Using index; Using temporary
+explain select distinct f1, f2 from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	NULL	PRIMARY	5	NULL	3	Using index for group-by; Using temporary
+drop table t1;

--- 1.90/mysql-test/t/select.test	2005-11-03 13:55:07 +03:00
+++ 1.91/mysql-test/t/select.test	2005-11-10 23:54:37 +03:00
@@ -2729,3 +2729,13 @@
 select * from t1 where f2 <= '2005-09-31';
 select * from t1 where f2 <= '2005-09-3a';
 drop table t1;
+
+#
+# Bug #13293 Wrongly used index results in endless loop.
+#
+create table t1 (f1 int, f2 char(1), primary key(f1,f2)) engine=innodb;
+insert into t1 values ( 1,"e"),(2,"a"),( 3,"c"),(4,"d");
+alter table t1 drop primary key, add primary key (f2, f1);
+explain select distinct f1 a, f1 b from t1;
+explain select distinct f1, f2 from t1;
+drop table t1;