Fixed bug #28449: a crash may happen at some rare conditions when

a temporary table has grown out of heap memory reserved for it and 
the remaining disk space is not big enough to store the table as
a MyISAM table.

The crash happens because the function create_myisam_from_heap
does not handle safely the mem_root structure associated 
with the converted table in the case when an error has occurred.


sql/sql_select.cc:
  Fixed bug #28449: a crash may happen at some rare conditions when
  a temporary table has grown out of heap memory reserved for it and 
  the remaining disk space is not big enough to store the table as
  a MyISAM table.
  
  The crash happens because the function create_myisam_from_heap
  does not handle safely the mem_root structure associated 
  with the converted table in the case when an error has occurred.
  
  As it's hard to create a sitiation that would throw an error 
  a special code has been added that raises an error for a newly 
  created test called error_simulation.
mysql-test/r/error_simulation.result:
  New BitKeeper file ``mysql-test/r/error_simulation.result''
  
  Added a test case for bug #28449.
mysql-test/t/error_simulation-master.opt:
  New BitKeeper file ``mysql-test/t/error_simulation-master.opt''
mysql-test/t/error_simulation.test:
  New BitKeeper file ``mysql-test/t/error_simulation.test''
  
  Added a test case for bug #28449.

1 files changed, 19 insertions, 0 deletions

diff --git a/mysql-test/r/error_simulation.result b/mysql-test/r/error_simulation.result
new file mode 100644
index 00000000000..805e8fabbd8
--- /dev/null
+++ b/mysql-test/r/error_simulation.result
@@ -0,0 +1,19 @@
+DROP TABLE IF EXISTS t1;
+Warnings:
+Note	1051	Unknown table 't1'
+CREATE TABLE t1 (
+a varchar(32) character set utf8 collate utf8_bin NOT NULL,
+b varchar(32) character set utf8 collate utf8_bin NOT NULL )
+ENGINE=MyISAM DEFAULT CHARSET=utf8;
+INSERT INTO t1 VALUES
+('AAAAAAAAAA','AAAAAAAAAA'), ('AAAAAAAAAB','AAAAAAAAAB '),
+('AAAAAAAAAB','AAAAAAAAAB'), ('AAAAAAAAAC','AAAAAAAAAC'),
+('AAAAAAAAAD','AAAAAAAAAD'), ('AAAAAAAAAE','AAAAAAAAAE'),
+('AAAAAAAAAF','AAAAAAAAAF'), ('AAAAAAAAAG','AAAAAAAAAG'),
+('AAAAAAAAAH','AAAAAAAAAH'), ('AAAAAAAAAI','AAAAAAAAAI'),
+('AAAAAAAAAJ','AAAAAAAAAJ'), ('AAAAAAAAAK','AAAAAAAAAK');
+set tmp_table_size=1024;
+SELECT MAX(a) FROM t1 GROUP BY a,b;
+ERROR 23000: Can't write; duplicate key in table ''
+set tmp_table_size=default;
+DROP TABLE t1;