MySQL Bugs: #41026: maria: Duplicate entry '...' for key 'PRIMARY' in sysbench OLTP

Bug #41026	maria: Duplicate entry '...' for key 'PRIMARY' in sysbench OLTP_RW test
Submitted:	25 Nov 2008 19:08	Modified:	4 Dec 2008 13:55
Reporter:	Alexey Stroganov	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server	Severity:	S3 (Non-critical)
Version:	6.0.8-release	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
Duplicate entry '...' for key 'PRIMARY' error happens in sysbench OLTP_RW test for Maria. Issue observed when number of threads are higher than 64.

Example of sysbench output:
...
Doing OLTP test.
Running mixed OLTP test
Using Uniform distribution
Using "BEGIN" for starting transactions
Using auto_inc on the id column
Threads started!
ALERT: failed to execute mysql_stmt_execute(): Err1062 Duplicate entry '408025' for key 'PRIMARY'
FATAL: database error, exiting...
Done.

How to repeat:
There is no repeatable test case. One need to run series of sysbench OLT_RW tests against Maria server. Instructions will be added later.

Hi Ranger. For me it's a bug only if the primary key is auto_increment and one is always inserting NULL into it (i.e. values autogenerated by the server, not specified by the client); is this the case in the test?

Today on Windows 2008 I've observed this issue for other engines (MyISAM/InnoDB) as well. I don't know what is special to Maria that on Linux I saw such issue for this engine only and why other engines are not affected. I will try to isolate this issue and will update bug report with my findings.

It turned out that this issue was caused by bug in sysbench that didn't properly perform lock/unlock.