Fixed lp:879939 "assertion in ha_maria::enable_indexes with derived_with_keys=on"

Honor unique/not unique when creating keys for internal tempory tables.
Added new variables to be used to limit how keys are created for internal temporary tables.


include/maria.h:
  Added maria_max_key_length() and maria_max_key_segments()
include/myisam.h:
  Added myisam_max_key_length() and myisam_max_key_segments()
mysql-test/r/mysql.result:
  Drop all used tables
mysql-test/r/subselect4.result:
  Added test case for lp:879939
mysql-test/t/mysql.test:
  Drop all used tables
mysql-test/t/subselect4.test:
  Added test case for lp:879939
sql/mysql_priv.h:
  Added internal_tmp_table_max_key_length and internal_tmp_table_max_key_segments to be used to limit how keys for derived tables are created.
sql/mysqld.cc:
  Added internal_tmp_table_max_key_length and internal_tmp_table_max_key_segments to be used to limit how keys for derived tables are created.
sql/share/errmsg.txt:
  Added new error message for internal errors
sql/sql_select.cc:
  Give error if we try to create a wrong key (this error should never happen)
  Honor unique/not unique when creating keys for internal tempory tables.
storage/maria/ha_maria.cc:
  Added change_table_ptr() to ensure that external_ref points always to the correct table.
  (Not having this caused an assert in the included test)
storage/maria/ha_maria.h:
  Added change_table_ptr() to ensure that external_ref points always to the correct table.
storage/maria/ma_check.c:
  Fixed bug in Duplicate key error printing (now row position is printed correctly)
storage/maria/ma_create.c:
  maria_max_key_length() -> _ma_max_key_length()
storage/maria/ma_info.c:
  Added extern function maria_max_key_length() to calculate the max key length based on current block size.
storage/maria/ma_open.c:
  maria_max_key_length() -> _ma_max_key_length()
storage/maria/maria_def.h:
  maria_max_key_length() -> _ma_max_key_length()
storage/myisam/ha_myisam.cc:
  Added change_table_ptr() to ensure that external_ref points always to the correct table.
  (Not having this caused an assert in the included test)
storage/myisam/ha_myisam.h:
  Added change_table_ptr() to ensure that external_ref points always to the correct table.

1 files changed, 35 insertions, 0 deletions

diff --git a/mysql-test/r/subselect4.result b/mysql-test/r/subselect4.result
index 386ae0bdbde..bdc04ca2a11 100644
--- a/mysql-test/r/subselect4.result
+++ b/mysql-test/r/subselect4.result
@@ -2104,3 +2104,38 @@ NULL
 deallocate prepare st1;
 drop table t1, t2, t3;
 set optimizer_switch=@subselect4_tmp;
+#
+# LP bug #879939: assertion in ha_maria::enable_indexes with derived_with_keys=on
+#
+CREATE TABLE t2 ( a varchar(3)) ;
+INSERT INTO t2 VALUES ('USA'),('USA'),('USA'),('USA'),('USA');
+CREATE TABLE t1 ( a varchar(3), b varchar(35)) ENGINE=MyISAM;
+INSERT INTO t1 VALUES ('USA','Lansing'),('USA','Laredo'),('USA','Las Vegas'),('USA','Lexington-Fayett'),('USA','Lincoln'),('USA','Little Rock'),('USA','Livonia'),('USA','Long Beach'),('USA','Los Angeles'),('USA','Louisville'),('USA','Lowell'),('USA','Lubbock'),('USA','Macon'),('USA','Madison'),('USA','Manchester'),('USA','McAllen'),('USA','Memphis'),('USA','Mesa'),('USA','Mesquite'),('USA','Metairie'),('USA','Miami');
+CREATE TABLE t3 ( a varchar(35)) ENGINE=MyISAM;
+INSERT INTO t3 VALUES ('Miami');
+SET optimizer_switch = 'derived_with_keys=on';
+SET @@tmp_table_size=1024*4;
+explain SELECT * FROM (SELECT t1.* FROM t1, t2 ) AS alias1 JOIN t3 ON ( t3.a = alias1.b );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t3	system	NULL	NULL	NULL	NULL	1	
+1	PRIMARY	<derived2>	ref	key0	key0	39	const	10	
+2	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	5	
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	21	Using join buffer (flat, BNL join)
+SELECT * FROM (SELECT t1.* FROM t1, t2 ) AS alias1 JOIN t3 ON ( t3.a = alias1.b );
+a	b	a
+USA	Miami	Miami
+USA	Miami	Miami
+USA	Miami	Miami
+USA	Miami	Miami
+USA	Miami	Miami
+SET @@tmp_table_size=1024*1024*16;
+SELECT * FROM (SELECT t1.* FROM t1, t2 ) AS alias1 JOIN t3 ON ( t3.a = alias1.b );
+a	b	a
+USA	Miami	Miami
+USA	Miami	Miami
+USA	Miami	Miami
+USA	Miami	Miami
+USA	Miami	Miami
+drop table t1,t2,t3;
+SET optimizer_switch= @@global.optimizer_switch;
+set @@tmp_table_size= @@global.tmp_table_size;