MySQL Error: "Unknown table engine 'InnoDBopt'"

I'm getting the following error on some code from an old app:

A Database Error Occurred
Error Number: 1286

Unknown table engine 'InnoDBopt'

INSERT INTO `sessions` (`session_id`, `ip_address`, `user_agent`, `last_activity`) VALUES ('2ef196aba7f060308be6b7bc1133671f', '127.0.0.1', 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) Ap', 1290342372)

I'm using MySQL version 5.1.36. This app was developed a while ago, so most likely I jus开发者_运维问答t need to downgrade my MySQL version to run this? If so, please advise what version I need to run this.

Edit: To clarify, I had to copy my database from one mysql installation to another, so I copied everything inside `c:/mysql/data' to the other installation of MySQL, that's likely what's causing this issue.

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Make sure the mysql user can write to /tmp. I got 'Unknown table engine InnoDB' after restore where /tmp was not writable for that user.

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There is another reason why INNODB engine is absent from MySQL. If your innodb_buffer_pool_size variable is too high and MySQL can't allocate the buffer it will disable the INNODB engine.

You should see something like this in the error log :

140204 13:12:26  InnoDB: Initializing buffer pool, size = 4.9G
140204 13:12:26  InnoDB: Error: cannot allocate 5242896384 bytes of
InnoDB: memory with malloc! Total allocated memory
InnoDB: by InnoDB 36878736 bytes. Operating system errno: 12
InnoDB: Check if you should increase the swap file or
InnoDB: ulimits of your operating system.
InnoDB: On FreeBSD check you have compiled the OS with
InnoDB: a big enough maximum process size.
InnoDB: Note that in most 32-bit computers the process
InnoDB: memory space is limited to 2 GB or 4 GB.
InnoDB: We keep retrying the allocation for 60 seconds...
140204 13:13:26InnoDB: Fatal error: cannot allocate the memory for the buffer pool
140204 13:13:26 [ERROR] Plugin 'InnoDB' init function returned error.
140204 13:13:26 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.

This error was logged on a server with 1GB of RAM while the buffer pool request 4.9G

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As suggested by Pekka, there is no engine 'InnoDBopt'

Try show engines;

If mysql return something like

+------------+----------+----
| Engine | Support | ...
+------------+----------+----
| InnoDB | DISABLED | ...

Most likely engine innodb has been disabled.
Look for option skip-innodb in your mysql configuration (such as my.cnf),
comment out this option,
restart mysql daemon, it should fix

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where is the table engine define? in my.cnf? check the spelling in my.cnf ... "opt" sounds like a path to a log file or something defined in the config file.

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Run SHOW CREATE TABLE sessions and then run SHOW engines

You will see something like ENGINE=xyz at he end of the first command result

xyz has to be in the list returned by SHOW engines

Edit: To be more explicit: The result of SHOW CREATE TABLE sessions is somethig like:

Table: sessions Create Table: CREATE TABLE sessions ( ................ ) ENGINE=xyz

where xyz could be MyIssam , Innodb, etc.