I have a production database where I have renamed several column’s that are foreign keys. Obviously mysql makes this a real pain to do in my experience.
My solution was to drop all the indexes and foreign keys, rename the id columns, and then re-add the indexes and foreign keys.
This works great on mysql 5.1 on windows for the development database.
I went to run my migration script on my debian server, which is also using mysql 5.1, and it gives the following error:
mysql> ALTER TABLE `company_to_module`
-> ADD CONSTRAINT `FK82977604FE40A062` FOREIGN KEY (`company_id`) REFERENCES `company` (`company_id`) ON DELETE RESTRICT ON UPDATE RESTRICT;
ERROR 1005 (HY000): Can't create table 'jobprep_production.#sql-44a5_76' (errno: 150)
There are no values in this table that would conflict with the foreign key I am trying to add. The database hasn’t changed. The foreign key DID exist before… so the data is fine. Let’s not mention that I took the SAME database that I have on the server and it migrates fine on Windows. But these same foreign key migrations are not taking on Debian.
The columns are using the same type – BIGINT (20)
The names do in fact exist in their respective tables.
The tables are innodb. They already have foreign keys in other columns as it is. This is not a new database.
I cannot drop tables because this is a production database.
The tables “as is” in my database:
CREATE TABLE `company_to_module` (
`company_id` bigint(20) NOT NULL,
`module_id` bigint(20) NOT NULL,
KEY `FK8297760442C8F876` (`module_id`),
KEY `FK82977604FE40A062` (`company_id`) USING BTREE,
CONSTRAINT `FK8297760442C8F876` FOREIGN KEY (`module_id`) REFERENCES `module` (`module_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
And
Create Table: CREATE TABLE `company` (
`company_id` bigint(20) NOT NULL AUTO_INCREMENT,
`name` varchar(255) DEFAULT NULL,
`address` varchar(255) DEFAULT NULL,
`postal_code` varchar(255) DEFAULT NULL,
`province_id` bigint(20) DEFAULT NULL,
`phone_number` varchar(255) DEFAULT NULL,
`is_enabled` bit(1) DEFAULT NULL,
`director_id` bigint(20) DEFAULT NULL,
`homepage_viewable` bit(1) NOT NULL DEFAULT b'1',
`courses_created` int(10) NOT NULL DEFAULT '0',
`header_background` varchar(25) DEFAULT '#172636',
`display_name` varchar(25) DEFAULT '#ffffff',
`tab_background` varchar(25) DEFAULT '#284767',
`tab_text` varchar(25) DEFAULT '#ffffff',
`hover_tab_background` varchar(25) DEFAULT '#284767',
`hover_tab_text` varchar(25) DEFAULT '#f2e0bd',
`selected_tab_background` varchar(25) DEFAULT '#f5f5f5',
`selected_tab_text` varchar(25) DEFAULT '#172636',
`hover_table_row_background` varchar(25) DEFAULT '#c0d2e4',
`link` varchar(25) DEFAULT '#4e6c92',
PRIMARY KEY (`company_id`),
KEY `FK61AE555A71DF3E03` (`province_id`),
KEY `FK61AE555AAC50C977` (`director_id`),
CONSTRAINT `company_ibfk_1` FOREIGN KEY (`director_id`) REFERENCES `user_account` (`user_account_id`),
CONSTRAINT `FK61AE555A71DF3E03` FOREIGN KEY (`province_id`) REFERENCES `province` (`province_id`)
) ENGINE=InnoDB AUTO_INCREMENT=24 DEFAULT CHARSET=utf8
Here is the innodb status:
------------------------
LATEST FOREIGN KEY ERROR
------------------------
110415 3:14:34 Error in foreign key constraint of table jobprep_production/#sql-44a5_1bc:
FOREIGN KEY (`company_id`) REFERENCES `company` (`company_id`) ON DELETE RESTRICT ON UPDATE RESTRICT:
Cannot resolve column name close to:
) ON DELETE RESTRICT ON UPDATE RESTRICT
If I try and drop the index from ‘company_to_module’, I get this error:
#1025 - Error on rename of './jobprep_production/#sql-44a5_23a' to './jobprep_production/company_to_module' (errno: 150)
Here are my innodb variables:
+---------------------------------+------------------------+
| Variable_name | Value |
+---------------------------------+------------------------+
| innodb_adaptive_hash_index | ON |
| innodb_additional_mem_pool_size | 1048576 |
| innodb_autoextend_increment | 8 |
| innodb_autoinc_lock_mode | 1 |
| innodb_buffer_pool_size | 8388608 |
| innodb_checksums | ON |
| innodb_commit_concurrency | 0 |
| innodb_concurrency_tickets | 500 |
| innodb_data_file_path | ibdata1:10M:autoextend |
| innodb_data_home_dir | |
| innodb_doublewrite | ON |
| innodb_fast_shutdown | 1 |
| innodb_file_io_threads | 4 |
| innodb_file_per_table | OFF |
| innodb_flush_log_at_trx_commit | 1 |
| innodb_flush_method | |
| innodb_force_recovery | 0 |
| innodb_lock_wait_timeout | 50 |
| innodb_locks_unsafe_for_binlog | OFF |
| innodb_log_buffer_size | 1048576 |
| innodb_log_file_size | 5242880 |
| innodb_log_files_in_group | 2 |
| innodb_log_group_home_dir | ./ |
| innodb_max_dirty_pages_pct | 90 |
| innodb_max_purge_lag | 0 |
| innodb_mirrored_log_groups | 1 |
| innodb_open_files | 300 |
| innodb_rollback_on_timeout | OFF |
| innodb_stats_on_metadata | ON |
| innodb_support_xa | ON |
| innodb_sync_spin_loops | 20 |
| innodb_table_locks | ON |
| innodb_thread_concurrency | 8 |
| innodb_thread_sleep_delay | 10000 |
+---------------------------------+------------------------+
I also want to add that while I was playing with adding the foreign keys, mysql corrupted my database and destroyed it. I had to reload from a backup to try again.
Help? :/
I have simply applied the refactorings using Windows and then reimported the database into Debian – it works.
I think it’s safe to say that something was messed up on the Debian server, or with the linux version of Mysql – perhaps a bug in 5.1 build?
Anyway, I have also upgraded the ram on the server from 1gb to 2gb, and these problems have gone away.
I think MySQL maybe just didn’t have enough ram to complete the operation. If that was the case (and it seems to be), I think MySQL should have simply said so rather than spitting out these errors – making me and everyone here think it was a syntax or a schema-related problem.
Anyway, thanks for those that tried to help. At least it helped me to isolate all the things it couldn’t have been.