MySQL Bugs: #115913: instant ddl crash

Bug #115913	instant ddl crash
Submitted:	23 Aug 2024 7:52	Modified:	23 Aug 2024 10:08
Reporter:	zongyi chen (OCA)	Email Updates:
Status:	Duplicate	Impact on me:	None
Category:	MySQL Server	Severity:	S6 (Debug Builds)
Version:		OS:	Any
Assigned to:		CPU Architecture:	Any
Tags:	instant ddl

Description:
CREATE TABLE `tt_1056` (
  `a` int DEFAULT NULL,
  `d1` double DEFAULT NULL,
  `v2` varchar(14) DEFAULT NULL,
  `t3` tinyint(1) DEFAULT NULL,
  `v4` varchar(16) DEFAULT NULL,
  `i5` int DEFAULT NULL,
  `i6` int NOT NULL AUTO_INCREMENT,
  `gN101` varchar(16) GENERATED ALWAYS AS (concat(substr(`v4`,1,11),substr(`v4`,1,5))) VIRTUAL,
  KEY `tt_1056i0` (`d1` DESC,`i5`,`i6`,`t3`,`v4` DESC,`v2`),
  KEY `tt_1056i1` (`i6` DESC,`t3` DESC,`i5`),
  KEY `tt_1056i2` (`i5`),
  KEY `tt_1056i3` (`i5`,`i6`)
);

insert into tt_1056(a, d1, v2, t3, v4, i5, i6) values(1, 0, 'test', 1, '', 1, 587891);

alter table tt_1056 drop column a,algorithm = instant;

insert into tt_1056(d1, v2, t3, v4, i5, i6) values(0, 'test', 1, '', 1, 587892);

START TRANSACTION;

DELETE FROM tt_1056;

SET DEBUG = "+d, compare_end_range";

SELECT * FROM tt_1056  WHERE gN101 = 'test';

UPDATE tt_1056 SET i6 = 587891 WHERE d1 = 0.00000;

SET DEBUG = "-d, compare_end_range";

COMMIT;

DROP TABLE tt_1056;

How to repeat:
CREATE TABLE `tt_1056` (
  `a` int DEFAULT NULL,
  `d1` double DEFAULT NULL,
  `v2` varchar(14) DEFAULT NULL,
  `t3` tinyint(1) DEFAULT NULL,
  `v4` varchar(16) DEFAULT NULL,
  `i5` int DEFAULT NULL,
  `i6` int NOT NULL AUTO_INCREMENT,
  `gN101` varchar(16) GENERATED ALWAYS AS (concat(substr(`v4`,1,11),substr(`v4`,1,5))) VIRTUAL,
  KEY `tt_1056i0` (`d1` DESC,`i5`,`i6`,`t3`,`v4` DESC,`v2`),
  KEY `tt_1056i1` (`i6` DESC,`t3` DESC,`i5`),
  KEY `tt_1056i2` (`i5`),
  KEY `tt_1056i3` (`i5`,`i6`)
);

insert into tt_1056(a, d1, v2, t3, v4, i5, i6) values(1, 0, 'test', 1, '', 1, 587891);

alter table tt_1056 drop column a,algorithm = instant;

insert into tt_1056(d1, v2, t3, v4, i5, i6) values(0, 'test', 1, '', 1, 587892);

START TRANSACTION;

DELETE FROM tt_1056;

SET DEBUG = "+d, compare_end_range";

SELECT * FROM tt_1056  WHERE gN101 = 'test';

UPDATE tt_1056 SET i6 = 587891 WHERE d1 = 0.00000;

SET DEBUG = "-d, compare_end_range";

COMMIT;

DROP TABLE tt_1056;

fixed by:
@@ -2950,9 +2950,9 @@ static MY_ATTRIBUTE((warn_unused_result)) bool row_sel_store_mysql_field_func(
     }
   } else {
     /* Field is stored in the row. */
-
-    data = rec_get_nth_field_instant(rec, offsets, field_no, rec_index, &len,
-                                     &col_convert_heap);
+    const dict_index_t* index_tmp = clust_templ_for_sec == true ? prebuilt_index : rec_index;
+    data = rec_get_nth_field_instant(rec, offsets, field_no, index_tmp, &len,
+                                    &col_convert_heap);
 
     if (len == UNIV_SQL_NULL) {
       /* MySQL assumes that the field for an SQL

Hi Mr. chen,

Thank you very much for your bug report.

We tried to repeat it with 8.0.39, 8.4.2 and 9.0.1 and in each one we get the following error:

ERROR 1193 (HY000) at line 15: Unknown system variable 'DEBUG'

Hence, you have to add some definitions in your test case.

Can't repeat.

refer to:https://bugs.mysql.com/bug.php?id=115890&thanks=4
is same bug

Hi Mr. chen,

You have not specified anywhere in  that this is a debug binary.

With debug binary, server crashes.

However, this is a duplicate bug of the following one:

https://bugs.mysql.com/bug.php?id=115890

Please, do not create duplicate bugs in our bugs forum.

Duplicate.

it happened in realese too. 
SET DEBUG = "+d, compare_end_range";  is to make it stable to reproduce

Hi,

In 8.0.39 , 8.4.2 and 9.0.1 releases (our official binaries) we always get the same error:

ERROR 1193 (HY000) at line 15: Unknown system variable 'DEBUG'

Hi,

Only one more comment.

Without "SET DEBUG .....", our official release binaries of 8.0.39, 8.4.2 and 9.0.1 work without the problem what so ever .... We do not even get the slightest warning.

Duplicate.