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Bug #46159: simple query that never returns

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The external 'for' loop in remove_dup_with_compare() handled 
HA_ERR_RECORD_DELETED by just starting over without advancing 
to the next record which caused an infinite loop. 
 
This condition could be triggered on certain data by a SELECT 
query containing DISTINCT, GROUP BY and HAVING clauses. 

Fixed remove_dup_with_compare() so that we always advance to 
the next record when receiving HA_ERR_RECORD_DELETED from 
rnd_next(). 

mysql-test/r/distinct.result:
  Added a test case for bug #46159.
mysql-test/t/distinct.test:
  Added a test case for bug #46159.
sql/sql_select.cc:
  Fixed remove_dup_with_compare() so that we always advance to 
  the next record when receiving HA_ERR_RECORD_DELETED from 
  rnd_next().
This commit is contained in:
Alexey Kopytov 2009-09-06 00:42:17 +04:00
parent 354f5f7bac
commit 505346028f
3 changed files with 74 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
mysql-test/r/distinct.result
View File

@ -763,4 +763,34 @@ a b d c
1 2 0 2 1 2 0 2
1 2 0 3 1 2 0 3
DROP TABLE t1; DROP TABLE t1;
#
# Bug #46159: simple query that never returns
#
SET @old_max_heap_table_size = @@max_heap_table_size;
SET @@max_heap_table_size = 16384;
SET @old_sort_buffer_size = @@sort_buffer_size;
SET @@sort_buffer_size = 32804;
CREATE TABLE t1(c1 int, c2 VARCHAR(20));
INSERT INTO t1 VALUES (1, '1'), (1, '1'), (2, '2'), (3, '1'), (3, '1'), (4, '4');
INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1;
INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1;
INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1;
INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1;
INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1;
INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1;
INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1;
INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1;
SELECT c1, c2, COUNT(*) FROM t1 GROUP BY c1 LIMIT 4;
c1 c2 COUNT(*)
1 1 2
2 2 1
3 1 2
4 4 1
SELECT DISTINCT c2 FROM t1 GROUP BY c1 HAVING COUNT(*) > 1;
c2
1
5
DROP TABLE t1;
SET @@sort_buffer_size = @old_sort_buffer_size;
SET @@max_heap_table_size = @old_max_heap_table_size;
End of 5.1 tests End of 5.1 tests

40
mysql-test/t/distinct.test
View File

@ -573,4 +573,44 @@ SELECT DISTINCT a, b, d, c FROM t1;
DROP TABLE t1; DROP TABLE t1;
--echo #
--echo # Bug #46159: simple query that never returns
--echo #
# Set max_heap_table_size to the minimum value so that GROUP BY table in the
# SELECT query below gets converted to MyISAM
SET @old_max_heap_table_size = @@max_heap_table_size;
SET @@max_heap_table_size = 16384;
# Set sort_buffer_size to the mininum value so that remove_duplicates() calls
# remove_dup_with_compare()
SET @old_sort_buffer_size = @@sort_buffer_size;
SET @@sort_buffer_size = 32804;
CREATE TABLE t1(c1 int, c2 VARCHAR(20));
INSERT INTO t1 VALUES (1, '1'), (1, '1'), (2, '2'), (3, '1'), (3, '1'), (4, '4');
# Now we just need to pad the table with random data so we have enough unique
# values to force conversion of the GROUP BY table to MyISAM
INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1;
INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1;
INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1;
INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1;
INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1;
INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1;
INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1;
INSERT INTO t1 SELECT 5 + 10000 * RAND(), '5' FROM t1;
# First rows of the GROUP BY table that will be processed by
# remove_dup_with_compare()
SELECT c1, c2, COUNT(*) FROM t1 GROUP BY c1 LIMIT 4;
# The actual test case
SELECT DISTINCT c2 FROM t1 GROUP BY c1 HAVING COUNT(*) > 1;
# Cleanup
DROP TABLE t1;
SET @@sort_buffer_size = @old_sort_buffer_size;
SET @@max_heap_table_size = @old_max_heap_table_size;
--echo End of 5.1 tests --echo End of 5.1 tests

3
sql/sql_select.cc
View File

@ -13665,7 +13665,10 @@ static int remove_dup_with_compare(THD *thd, TABLE *table, Field **first_field,
if (error) if (error)
{ {
if (error == HA_ERR_RECORD_DELETED) if (error == HA_ERR_RECORD_DELETED)
{
error= file->rnd_next(record);
continue; continue;
}
if (error == HA_ERR_END_OF_FILE) if (error == HA_ERR_END_OF_FILE)
break; break;
goto err; goto err;