MySQL Bugs: #72419: More troubleshooting info for "unable to purge a record" message

Bug #72419	More troubleshooting info for "unable to purge a record" message
Submitted:	22 Apr 2014 10:40	Modified:	24 Feb 2016 14:17
Reporter:	Daniël van Eeden (OCA)	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Documentation	Severity:	S3 (Non-critical)
Version:	5.6.16	OS:	Any
Assigned to:	Daniel Price	CPU Architecture:	Any
Tags:	innodb, purge, troubleshooting

Description:
I found this messages in the error log (customer data removed):

2014-04-15 16:13:14 7f935caa4700  InnoDB: unable to purge a record
InnoDB: tuple DATA TUPLE: 6 fields;
 0: len 4; hex *******************
 1: len 1; hex *******************
 2: len 14; hex *******************
 3: len 7; hex *******************
 4: len 11; hex *******************
 5: len 7; hex *******************

InnoDB: record PHYSICAL RECORD: n_fields 6; compact format; info bits 0
 0: len 4; hex *******************
 1: len 1; hex *******************
 2: len 14; hex *******************
 3: len 7; hex *******************
 4: len 11; hex *******************
 5: len 7; hex *******************

space 891175 offset 7573 (85 records, index id 2163180)
InnoDB: Submit a detailed bug report to http://bugs.mysql.com
140415 16:16:03 mysqld_safe Number of processes running now: 0
140415 16:16:03 mysqld_safe mysqld restarted

There is no info about how to debug this.

How to repeat:
Unknown...

Suggested fix:
Add a link to the documentation.

Some troubleshooting steps:
1. Try to find which table/file this is about:
SELECT * FROM INFORMATION_SCHEMA.INNODB_SYS_DATAFILES WHERE space=891175;

2. You might want to try and see if you can reproduce this

3. Is it reproducable with and without changebuffer?

See Bug #72420 for some more possible troubleshooting steps.

Thank you for the reasonable docs request.

Please clarify what the documentation request is. The bug report asks to add a link (from where?) to the documentation (which page?), but I can't see what it suggests to change in the docs.
Stefan

In the error message there should be a link to the documentation. The link should go to the page about 'InnoDB: unable to purge a record', which AFAIK doesn't exist yet.

The documentation should describe steps to figure out what caused the message and if possible how to correct the issue.

See also: Bug #70214, Bug #71720

The documentation should help to answer questions like:
- What is the meaning of this message?
- What is the result of this message? Should I restart/restore/etc ?
- Which table(s), tablespace(s) and/or index(es) are affected?
- What are probable causes?
- How do I fix this?
- Is this due to buffer pool? bp dump/restore? change buffer? filesystem issues? a crash? a enterprise backup bug?

Sorry, for some reason this bug report was never assigned back to me. So, there are two parts to it IIUC:
1) Create a new page in the InnoDB chapter.
2) Add a link to that page from the error message thrown.
The MySQL documentation team can take care of doing 1), and will then change this bug to a code bug (with a message explaining what to do), since 2) must be handled by MySQL Server development.
-Stefan

Posted by developer:
 
The error message was due to a code bug that was fixed in 5.5.45, 5.6.26, 5.7.8. 
Bug #19138298 / MySQL Bug #70214 RECORD IN INDEX WAS NOT FOUND ON ROLLBACK, TRYING TO INSERT 

Symptom details were added to the changelog entry for Bug #19138298 / MySQL Bug #70214 to help identify the release level that contains the fix.

Thank you for the bug report.