[MDEV-10521] database and tables became invisible Created: 2016-08-09  Updated: 2016-10-07  Resolved: 2016-10-07

Status: Closed
Project: MariaDB Server
Component/s: OTHER
Affects Version/s: 10.1.16
Fix Version/s: N/A

Type: Bug Priority: Major
Reporter: Gerrit W. Assignee: Unassigned
Resolution: Incomplete Votes: 0
Labels: need_feedback
Environment:

Windows 7 32 bit Embedded

Attachments: File mysql.ini.mariadb    

 Description   

We have the problem that our databases and tables became all of the sudden invisible during runtime. SHOW DATABASES and SHOW TABLES stopped returning anything. Nevertheless SELECTs and INSERTs still work if the correct database/table name is given. The error logs do not contain any information. Restarting the database does not resolve the problem. There were some changes to the database layout around the time when the problem set in, three additional tables were added and one unused table was deleted but it is uncertain if this caused the problem.
The problem is independent of the user and it's permissions. The root user can not see the databases, neither can a newly added user that has every permission possible. The skip-show-database option is definitely disabled.

Is there a general problem with running MariaDB on 32bit windows systems? We have experienced a bug that resulted in data loss before which was fixed in 10.1.14, so we are a bit concerned.

 Comments   
Comment by Vladislav Vaintroub [ 2016-08-09 ]

It would be helpful if you could take a minidump of the process, once this problem occurs (e.g task manager "Create dump" for mysqld.exe)

(So far there are no known systemic bug running MariaDB on Windows. MDEV-9977 that is likely that 'data loss bug' you mention. occured on all 32 bit platforms. But it might be that 32 bit binaries used under Windows a bit more often)

Comment by Vladislav Vaintroub [ 2016-08-09 ]

I could have actually misread the description. If "SHOW" returns an empty set, rather than hang, then minidump does not help.
But in this case you could use procmon as described here https://mariadb.com/kb/en/mariadb/how-to-use-procmon-to-trace-mysqldexe-filesystem-access/ (just for a single SHOW command), this could provide a valuable info,

Comment by Gerrit W. [ 2016-08-10 ]

thank you for the information and your help. The SHOW commands did indeed return empty sets and did not hang.
We have exported the content of the database and recreated the database using a freshly initialized datadir. Now everything is back to normal again.
However we made a copy of the original system. We will try to create a trace with procmon as soon as we have some time, probably next week.

Comment by Elena Stepanova [ 2016-09-09 ]

ftx, any news on this?

Comment by Elena Stepanova [ 2016-10-07 ]

Please comment to re-open the issue if you have more information.

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