Bug#4411

  Fix for server hang bug

BitKeeper/etc/logging_ok

@@ -5,6 +5,7 @@ Administrator@fred.
 Greg@greg-laptop.
 Miguel@light.local
 Sinisa@sinisa.nasamreza.org
+acurtis@pcgem.rdg.cyberkinetica.com
 ahlentz@co3064164-a.rochd1.qld.optusnet.com.au
 akishkin@work.mysql.com
 antony@ltantony.dsl-verizon.net

mysql-test/r/heap.result

@@ -217,3 +217,13 @@ DELETE from t1 where a < 100;
 SELECT * from t1;
 a
 DROP TABLE t1;
+CREATE TABLE `job_titles` (
+`job_title_id` int(6) unsigned NOT NULL default '0',
+`job_title` char(18) NOT NULL default '',
+PRIMARY KEY  (`job_title_id`),
+UNIQUE KEY `job_title_id` (`job_title_id`,`job_title`)
+) TYPE=HEAP;
+SELECT MAX(job_title_id) FROM job_titles;
+MAX(job_title_id)
+NULL
+DROP TABLE job_titles;

mysql-test/t/heap.test

@@ -147,3 +147,17 @@ INSERT into t1 values (1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11);
 DELETE from t1 where a < 100;
 SELECT * from t1;
 DROP TABLE t1;
+
+#
+# Bug#4411 Server hangs when trying to SELECT MAX(id) from an empty HEAP table
+#
+CREATE TABLE `job_titles` (
+  `job_title_id` int(6) unsigned NOT NULL default '0',
+  `job_title` char(18) NOT NULL default '',
+  PRIMARY KEY  (`job_title_id`),
+  UNIQUE KEY `job_title_id` (`job_title_id`,`job_title`)
+) TYPE=HEAP;
+
+SELECT MAX(job_title_id) FROM job_titles;
+
+DROP TABLE job_titles;

sql/opt_sum.cc

@@ -401,6 +401,7 @@ static bool find_range_key(TABLE_REF *ref, Field* field, COND *cond)
       /* Can't use this key, for looking up min() or max(), end if last one */
       if (key == 1)
 	return 0;
+      key>>=1; idx++;
     }
     ref->key_length=0;
     ref->key=idx;