MySQL Bugs: #31874: Failure for NDB update/delete with combined range and equality constraints

Bug #31874	Failure for NDB update/delete with combined range and equality constraints
Submitted:	26 Oct 2007 11:02	Modified:	6 Nov 2007 8:32
Reporter:	Kristian Nielsen	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Cluster: Cluster (NDB) storage engine	Severity:	S2 (Serious)
Version:	mysql-6.0, mysql-telco-6.2	OS:	Any
Assigned to:	Kristian Nielsen	CPU Architecture:	Any

Description:
create table t1 (
  a int not null primary key,
  b int
) engine = ndb;
insert into t1 values (7,2),(8,3),(10,4);
update t1 set b = 5 where a in (7,8) or a >= 10;

 -> "got unknown error from ndb"

The problem is a bug in the read_multi_range_next() call. This call is used to scan a table using a combination of primary key equality lookups and range scans. In the above example there are two primary key looks (a=7 or a=8) and one range scan (a >= 10).

In some cases, read_multi_range_next() fails to correctly set a flag to determine whether the current row comes from a primary key lookup or from a scan. When this happens, updates or deletes execute wrongly.

How to repeat:
Will comit test case.

Suggested fix:
Will commit patch.

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/36426

ChangeSet@1.2676, 2007-10-26 13:09:35+02:00, knielsen@ymer.(none) +4 -0
  Bug #31874: Failure for NDB update/delete with combined range and equality constraints
  
  In update/delete with read_multi_range, when mixing pk lookups and range
  scans, sometimes update/delete did not correctly distinguish whether
  the current row was from pk lookup or from scan. This caused query
  failure (or potentially memory corruption and crash).
  
  Fix by setting proper flags in the read_multi_range_next() method.

Pushed to mysql-5.1-telco-6.2 and mysql-5.1-telco-6.3

Pushed into 6.0.4-alpha

Documented in mysql-5.1.22-ndb-6.2.8, mysql-5.1.22-ndb-6.3.6, and 6.0.4 changelogs.

Please advise as to whether this fix will appear in 5.1-main and if so, the applicable version.

This will not appear in 5.1-main, as the bug is not in 5.1, it was introduced only in 6.0.

Closed, no further documentation required. Thanks for the info.