Bug #17371 Unable to dump a schema with invalid views
Submitted: 14 Feb 2006 11:02 Modified: 14 Jul 2006 16:44
Reporter: Kristian Koehntopp Email Updates:
Status: Closed Impact on me:
Category:MySQL Server: Views Severity:S1 (Critical)
Version:5.0.18 OS:Linux (Linux)
Assigned to: Tatiana Azundris Nuernberg CPU Architecture:Any

[14 Feb 2006 11:02] Kristian Koehntopp
It is possible to create view definitions that are invalid because they reference tables no longer present (because they have been dropped). mysqldump then stopps dumping with an error message.

How to repeat:
linux:~ # mysql-3340
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 6 to server version: 5.0.18-max-log

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

root@localhost [(none)]> create database boom;
Query OK, 1 row affected (0.00 sec)

root@localhost [(none)]> use boom
Database changed
root@localhost [boom]> create table basetable ( id serial );
Query OK, 0 rows affected (0.01 sec)

root@localhost [boom]> create view validview as select * from basetable;
Query OK, 0 rows affected (0.00 sec)

root@localhost [boom]> drop table basetable;
Query OK, 0 rows affected (0.00 sec)

root@localhost [boom]> select version();
| version()      |
| 5.0.18-max-log |
1 row in set (0.00 sec)

root@localhost [boom]> quit
linux:~ # mysqldump-3340 -u root --no-data boom
-- MySQL dump 10.10
-- Host: localhost    Database: boom
-- ------------------------------------------------------
-- Server version       5.0.18-max-log

/*!40101 SET NAMES utf8 */;
/*!40103 SET TIME_ZONE='+00:00' */;
mysqldump: Got error: 1356: View 'boom.validview' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them when using LOCK TABLES

Suggested fix:
Allow invalid views, and let mysqldump dump their definitions. Amend the definition of a view with a flag that marks it as INVALID or VALID, as Oracle does it.

This will also solve any dependency sorting problems with views that depend on views, and simplify the mysqldump code, which is currently doing horrible stuff with dummy tables acting as a stand-in for views not yet defined.
[14 Feb 2006 12:34] Valeriy Kravchuk
Thank you for a problem report. I would call it a feature request. And this feature will be useful for mysqldump only when it will become possible to create views based on non-existing objects. Not sure, that this will be done ever.
[14 Feb 2006 12:42] Kristian Koehntopp
Well, the example given is an example that is possible with mysql right now. 

Dropping "basetable" breaks current backup methods, and does so with no warning or error message on the drop. I consider that a bug, and not a feature request. mysqldump must not break in this situation, or there will be no backup with many customers installations.
[30 May 2006 12:49] Bugs System
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:

[26 Jun 2006 18:15] Tatiana Azundris Nuernberg
merged into 5.0.23 (main)
[14 Jul 2006 16:44] Paul DuBois
Noted in 5.0.23, 5.1.12 changelogs.

mysqldump would not dump views that had become invalid because a
table named in the view definition had been dropped. Instead, it quit
with an error message. Now you can specify the --force option to
cause mysqldump to keep going and write a SQL comment containing the
view definition to the dump output.