bzr commit into mysql-5.1-bugteam branch (Sergey.Glukhov:3408) Bug#51494

[Sergey Glukhov]

#At file:///home/gluh/MySQL/mysql-5.1-bugteam/ based on revid:omer@stripped

 3408 Sergey Glukhov	2010-03-19
      Bug#51494 crash with join, explain and 'sounds like' operator
      The crash happens because of discrepancy between values of
      conts_tables and join->const_table_map(make_join_statisctics).
      Calculation of conts_tables used condition with
      HA_STATS_RECORDS_IS_EXACT flag check. Calculation of
      join->const_table_map does not use this flag check.
      In case of MERGE table without union with index
      the table does not become const table and
      thus join_read_const_table() is not called
      for the table. join->const_table_map supposes
      this table is const and later in make_join_select
      this table is used for making&calculation const
      condition. As table record buffer is not populated
      it leads to crash.
      The fix is adding a check if an engine supports
      HA_STATS_RECORDS_IS_EXACT flag before updating
      join->const_table_map.
     @ mysql-test/r/merge.result
        test result
     @ mysql-test/t/merge.test
        test case
     @ sql/sql_select.cc
        adding a check if an engine supports
        HA_STATS_RECORDS_IS_EXACT flag before updating
        join->const_table_map.

    modified:
      mysql-test/r/merge.result
      mysql-test/t/merge.test
      sql/sql_select.cc
=== modified file 'mysql-test/r/merge.result'
--- a/mysql-test/r/merge.result	2010-03-03 10:49:03 +0000
+++ b/mysql-test/r/merge.result	2010-03-19 06:01:02 +0000
@@ -2286,4 +2286,16 @@ m1	CREATE TABLE `m1` (
 DROP TABLE m1;
 DROP TABLE `test@1`.`t@1`;
 DROP DATABASE `test@1`;
+#
+# Bug#51494c rash with join, explain and 'sounds like' operator
+#
+CREATE TABLE t1 (a INT) ENGINE=MYISAM;
+INSERT INTO t1 VALUES(1);
+CREATE TABLE t2 (b INT NOT NULL,c INT,d INT,e BLOB NOT NULL,
+KEY idx0 (d, c)) ENGINE=MERGE;
+EXPLAIN SELECT * FROM t1 NATURAL RIGHT JOIN
+t2 WHERE b SOUNDS LIKE e AND d = 1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+DROP TABLE t2, t1;
 End of 5.1 tests

=== modified file 'mysql-test/t/merge.test'
--- a/mysql-test/t/merge.test	2010-03-03 10:49:03 +0000
+++ b/mysql-test/t/merge.test	2010-03-19 06:01:02 +0000
@@ -1690,4 +1690,19 @@ DROP TABLE m1;
 DROP TABLE `test@1`.`t@1`;
 DROP DATABASE `test@1`;
 
+--echo #
+--echo # Bug#51494c rash with join, explain and 'sounds like' operator
+--echo #
+
+CREATE TABLE t1 (a INT) ENGINE=MYISAM;
+INSERT INTO t1 VALUES(1);
+
+CREATE TABLE t2 (b INT NOT NULL,c INT,d INT,e BLOB NOT NULL,
+KEY idx0 (d, c)) ENGINE=MERGE;
+
+EXPLAIN SELECT * FROM t1 NATURAL RIGHT JOIN
+t2 WHERE b SOUNDS LIKE e AND d = 1;
+
+DROP TABLE t2, t1;
+
 --echo End of 5.1 tests

=== modified file 'sql/sql_select.cc'
--- a/sql/sql_select.cc	2010-03-14 16:01:45 +0000
+++ b/sql/sql_select.cc	2010-03-19 06:01:02 +0000
@@ -2943,7 +2943,8 @@ make_join_statistics(JOIN *join, TABLE_L
       s->quick=select->quick;
       s->needed_reg=select->needed_reg;
       select->quick=0;
-      if (records == 0 && s->table->reginfo.impossible_range)
+      if (records == 0 && s->table->reginfo.impossible_range &&
+          (s->table->file->ha_table_flags() & HA_STATS_RECORDS_IS_EXACT))
       {
 	/*
 	  Impossible WHERE or ON expression


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