I have a very interesting case. Several of my InnoDB tables got somehow corrupted. The .frm files of the tables disappeared and only the .ibd files were left.
I thought no problem, I will restore these tables from the backup, so I deleted the .frm files and try to create the new tables with the same name, but every time I get "the table already exists", the .ibd file gets created, but the .frm not.
Basically now I cannot create InnoDB tables with the given names in the given database. My only solution was to create MyISAM tables instead, but I would still like to know how to resolve this.
Below is a detailed log of the events:
Try to create the table:
CREATE TABLE employee
( employee_id varchar(20) NOT NULL,
PRIMARY KEY (employee_login_id) USING BTREE )
ENGINE=InnoDB DEFAULT
CHARSET=utf8 PACK_KEYS=1 ROW_FORMAT=COMPRESSED
table already exists
Try to drop the table to show that it doesn't exist:
DROP TABLE employee
table doesn't exist
I manually deleted the employee.ibd file (there is no employee.frm file)
Try #1 again and receive the "table already exists" again
I have restarted MySQL, no change.
I have restarted the whole server, no change.
I cannot create an InnoDB table with the name "employee" in this tablespace anymore.
Any idea?
Information about a table is stored in two places:
Server-wide table.frm file
Storage-engine specific InnoDB dictionary
These two must be in-sync, but there is no reliable mechanism to enforce this consistency. Due to number of reasons InnoDB dictionary gets out of sync.
In your case there is an orphaned record in the dictionary. You need to delete it.
InnoDB doesn't provide any way to manually modify the dictionary records. But you can craft a fake table.frm (if innodb_file_per_table=ON then table.ibd too) files, put it into the database directory and drop the table.
Old versions of InnoDB might complain about mismatching SPACENO. Then check how to fix InnoDB dictionary
Related
I have MySQL running on SSDs, SSDs that I'm about to run out of space on. My webhost overcharges for SSDs and the majority of the data in MySQL is "archived" data (i.e. data that isn't actively used). I have larger HDDs that can hold this data. As such, I want to be able to move specific InnoDB tables from the SSDs to the HDDs.
One solution I've thought about and researched is moving the individual .ibd files (I have innodb_file_per_table enabled) for the specific tables in question to the HDDs and then symlink. However, researching this, it looks like that is a bad idea for InnoDB.
I've also seen that since 5.6, MySQL supports the DATA DIRECTORY command:
To create a new InnoDB file-per-table tablespace in a specific
location outside the MySQL data directory, use the DATA DIRECTORY =
absolute_path_to_directory clause of the CREATE TABLE statement.
Plan the location in advance, because you cannot use the DATA
DIRECTORY clause with the ALTER TABLE statement. The directory you
specify could be on another storage device with particular performance
or capacity characteristics, such as a fast SSD or a high-capacity
HDD.
The problem is, it looks like this is only supported for new tables. I want to do it for existing tables. Any tips on how? I'm running Percona MySQL, if it helps.
Thanks!
UPDATE: Here is what I tried, but I'm getting a syntax error:
CREATE TABLE abc_2 LIKE abc ENGINE=InnoDB DATA DIRECTORY='/xxx/mysql/archive/'
Apparently CREATE ... LIKE ... DATA DIRECTORY ... is a combination that is not supported.
Do SHOW CREATE TABLE to get the current definition. Edit it to add DATA DIRECTORY and INDEX_DIRECTORY. Then use the edited text to create the new table.
Then INSERT INTO new_tbl SELECT * FROM real_tbl; and shuffle the names: RENAME TABLE real_tbl TO old_tbl, new_tbl TO real_tbl;.
Verify the results and finally DROP old_tbl;
I have dealt with this problem myself, and eventually found a more elegant solution than 'create new - copy - switch': detaching, moving and re-importing the underlying tablespace files. This is much more efficient on large and/or heavily indexed tables as MySQL does not have to redo work it has already done.
In short, it comes down to the following steps:
FLUSH TABLES `table_name` FOR EXPORT;
While keeping the connection open, move the tablespace files in a shell:
$ mv /var/lib/mysql/database_name/table_name.{ibd,cfg} ~
Now back in MySQL release the lock, drop the table, re-create it with the correct DATA DIRECTORY and discard its tablespace:
UNLOCK TABLES;
SHOW CREATE TABLE `table_name`;
DROP TABLE `table_name`;
CREATE TABLE `table_name` /* ... */ DATA DIRECTORY='/path/to/desired/location';
ALTER TABLE `table_name` DISCARD TABLESPACE;
Now copy the moved tablespace files to the desired location:
$ cp -a ~/table_name.{ibd,cfg} /path/to/desired/location
And import them:
ALTER TABLE `table_name` IMPORT TABLESPACE;
More background and motivation for why 'create new - copy - switch' is inefficient can be found in a blogpost I wrote on this topic: https://www.moxio.com/blog/28/moving-individual-mysql-tables-on-disk.
We have our database stored in aruba (mysql.aruba.it) where there is a table called "task". Because of many changes in the requirements we decided to drop the table and create it again from 0 with different fields and constraints. The problem is that MySQL/Aruba won't let us create the table anymore. Or better, we can create another task table only with engine MyISAM but we need INNODB because we will use contraints and foreign keys in the table. So I have tried to create a MyISAM table and then convert it into INNODB but I get an error like this:
ALTER TABLE `task` ENGINE = INNODB
#1025 - Error on rename of './Sql689345_4/#sql-6962_1891f' to './Sql689345_4/task' (errno: -1)
I don't know why there is this problem with this table: for other tables we have we can drop them and re-create them as many times as we want.
Is there a way to fix it?
Not all Aruba databases accept InnoDB tables; verify on the "Engine" link inside the control panel if INNODB is in white (engaged) or in grey (disengaged); if your database does not support InnoDB tables you can ask a new database supporting InnoDB for free, opening an assistance ticket.
In order to convert a table from MyIsam to InnoDB, is not a good practice to use the command ALTER TABLE, I suggest to export your table in a .sql file, CREATE a new table with the required structure and the InnoDB engine, and then import the data from .sql file.
I have no idea what is going on. I have a table called project_share_invite. A few hours ago (in our production environment) I could no longer issue SELECTs against this table. MySQL claims the table does not exist, though it shows on show tables. The only noteworthy event that has happened on the machine today is a routine package upgrade (via apt).
mysql> use analytics;
Database changed
mysql> show tables like 'project_share_invite';
+--------------------------------------------+
| Tables_in_analytics (project_share_invite) |
+--------------------------------------------+
| project_share_invite |
+--------------------------------------------+
1 row in set (0.00 sec)
mysql> select count(*) from project_share_invite;
ERROR 1146 (42S02): Table 'analytics.project_share_invite' doesn't exist
Ideas? This doesn't make any sense to me.
Update: The files for the table are still present on disk (project_share_invite.frm and project_share_invite.idb respectively) and have content in them.
A quick restart of MySQL has not fixed this.
Update: Same results when using root account instead of specific user account.
Update: I am unable to recreate the tables either.
CREATE TABLE `analytics`.`project_share_invite` ( ... )
ERROR 1146 (42S02): Table 'analytics.project_share_invite' doesn't exist
Update: Should have checked the error logs first:
InnoDB: Load table 'analytics/project_share_invite' failed, the table has missing foreign key indexes.
Though I've no idea how it's got in this state.
Looks like you hit a known bug in MySQL where a foreign key constraint exists, but the associated index was dropped. See: http://bugs.mysql.com/bug.php?id=68148
Depending on the version of MySQL (Seems like you need 5.6 or >) you can fix this problem by turning off foreign key checking and then recreating the missing index(es).
SET FOREIGN_KEY_CHECKS=0;
You should check the structure using SHOW CREATE TABLE table name
Then use CREATE INDEX to recreate the missing indexes.
This error is usually caused by moving files around at the filesystem level.
Keep in mind that SHOW TABLES just reads the .frm file, but once you query the table, MySQL invokes the storage engine. InnoDB has its own internal way of managing metadata, in a "data dictionary" which is always stored in ibdata1.
So if you moved the datadir but forgot the ibdata1 file (or copied an ibdata1 from another instance), then the InnoDB data dictionary wouldn't know about the table, even though SHOW TABLES does.
Another possibility is that you copied data files around, and now they don't have the write ownership or file permissions. So for example the .frm file is readable but the .ibd is not. They should be owned and writeable by mysql:mysql.
If your apt upgrade changed file locations or file permissions, that could cause it too. I would advise using ls -l to verify the permissions on the files.
I have a mysql table y in database xxx which I attempted to change compression type before using
alter table y row_format=compressed key_block_size=8
the process stopped half way. I removed temp file '#sql-ib265.frm and #sql-ib265' in mysql lib directory and restarted the server. However
Now when I attempt the alter table y (with the same command above) again I get error.
ERROR 1050 (42S01) at line 1: Table 'xxx/#sql-ib265' already exists
I can't drop table 'xxx/#sql-ib265' because it can't be found.
what should I do?
Edit
Solution:
I ended up dropping the old database and recreate the database.
Try to restart mysql client with the --skip-auto-rehash option and try DROP TABLE again.
If above does not work, try this from MySQL Manual:
You have a corrupt innodb data dictionary..
https://dev.mysql.com/doc/refman/5.0/en/innodb-troubleshooting-datadict.html
Problem with Temporary Table
If MySQL crashes in the middle of an ALTER TABLE operation, you may end up with an orphaned temporary table inside the InnoDB tablespace. Using the Table Monitor, you can see listed a table with a name that begins with #sql-. You can perform SQL statements on tables whose name contains the character “#” if you enclose the name within backticks. Thus, you can drop such an orphaned table like any other orphaned table using the method described earlier. To copy or rename a file in the Unix shell, you need to put the file name in double quotation marks if the file name contains “#”.
There are two ways to fix this problem.
As other answer suggests, official MySQL documentation suggests to drop a specially crafted table. But please note in versions >= 5.1 you need to prefix table name with #mysql50#.
Move (use RENAME TO) all good tables to a temporary database, drop&recreate the original one and then move the tables back. See a blog post for details.
in additional I'm loging in with root to do the recover job but failed. then i chown the .frm file to meet the owner of mysql service and succeed.
For anyone still facing this problem, I have just followed the following steps to solve it, which (to me at least) seem far less daunting than other solutions:
Use mysqldump to back up the database with all its data.
Drop and recreate the database.
Reload the database and all its schema from the file generated in (1).
Because the orphaned tables are hidden anyway, they don't get backed up, so you end up with a database without them. I had all my procedures/functions scripted out anyway, so was able to restore them easily - if you don't, make sure you use the --routines parameter to dump those too.
My dump file was around 1.5GB for the database in question (so it's not small), and the whole thing was completed in a few minutes.
I had the same error. I fixed it by switching the order in which I dropped the tables at the beginning of the file:
DROP TABLE IF EXISTS table_name;
This line is repeated for each table. Tables with foreign keys need to be deleted before the tables with the primary keys to which they point.
I'm using mysql 5.1.41-3ubuntu12.10 and would like to know when my table was last ALTERed (or CREATEd, if it was never ALTERed).
SELECT * FROM information_schema.TABLES WHERE TABLE_SCHEMA = SCHEMA();
gives the CREATE and last UPDATE time, but not AFAICT the last ALTER time.
The answer depends somewhat on the storage engine. The most reliable indicator of when the table was last altered is to look at the modified time on the .frm file in the data directory. That file should be updated every time you alter the table, even for changes like updating a column default that don't require a table rebuild.
information_schema.tables.create_time is a bit of a misnomer, since that value actually changes most of the time when you alter a table. However, this is one area where the storage engine is relevant. If you do an alter without a rebuild (like changing a column default value) in InnoDB then information_schema.tables.create_time is updated, but if you do the same in MyISAM information_schema.tables.create_time is not updated. In both cases the .frm file should be updated, so I'd recommend you check the file timestamp for the most accurate data if you have access to it.