MySQL LOAD_FILE() loads null values

mysql

I'm attempting to load a directory of xml files into a database table as blobs. Each row would contain a corresponding blob file. When loading files via a python script into the table, values are inserted as null. This is also the case when running an equivalent command in the mysql command line.

At one point I was able to insert values after changing some folder permissions to mysql, but due to needed scripting privileges I had to modify ownership of the directory /var/lib/mysql/foo, thus values are being reinserted as null effectively breaking the script I wrote. I cannot remember the necessary change of directory permissions to do so.

The following are discussions of the topic:

http://bugs.mysql.com/bug.php?id=38403

along with

MySQL LOAD_FILE returning NULL

I copied my file to the location where MySQL has access to.
To know the location I used:

select @@secure_file_priv;

and it gave me /var/lib/mysql-files/.

Nothing else worked: neither turning off apparmor, nor changing ownership and permissions, nor merely granting the file privilege. So I rolled back most of that but the right directory still works. In my case.

My source is Raymond Nijland, here: https://dba.stackexchange.com/questions/190380/load-file-producing-null

Make sure:

there is execute permission on the parent directory
The FILE privilege must is explicily granted. (GRANT FILE on . TO user@localhost)
You have flushed privileges
You have logged out and logged back in

Example of permission on parent dir:


mysql> \! ls -ld `dirname /home/jlam/code/projectName/doc/filesForTesting/images/imageTest01.jpg`
drwxrwxr--. 2 jlam jlam 4096 May 12 14:22 /home/jlam/code/projectName/doc/filesForTesting/images

mysql> select hex(LOAD_FILE('/home/jlam/code/projectName/doc/filesForTesting/images/image

Test01.jpg'));
+-------------------------------------------------------------------------------------------------------------+
| hex(LOAD_FILE('/home/jlam/code/projectName/doc/filesForTesting/images/imageTest01.jpg')) |
+-------------------------------------------------------------------------------------------------------------+
| NULL                                                                                                        |
+-------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)



mysql> \! chmod o+x /home/jlam/code/projectName/doc/filesForTesting/images
mysql> \! ls -ld `dirname /home/jlam/code/projectName/doc/filesForTesting/images/imageTest01.jpg`
drwxrwxr-x. 2 jlam jlam 4096 May 12 14:22 /home/jlam/code/projectName/doc/filesForTesting/images
mysql> select hex(LOAD_FILE('/home/jlam/code/projectName/doc/filesForTesting/images/imageTest01.jpg'));
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| hex(LOAD_FILE('/home/jlam/code/projectName/doc/filesForTesting/images/imageTest01.jpg'))                                                                                                                                
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| FFD8FFE1001845786966000049492A00080000000000000000000000FFEC00114475636B7900010004000000500000FFE10407687474703A2F2F6E732E61646F62652E636F6D2F7861702F312E302F003C3F787061636B657420626567696E3D22EFBBBF222069643D2257354D304D7043656869487
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Example of user privileges:


16:38:09 (getImages) ~/code/projectName/doc/filesForTesting/images$ mysql -u eventCal -p eventCal
Enter password: 

mysql> show grants;
+-----------------------------------------------------------------------------------------------------------------+
| Grants for eventCal@localhost                                                                                   |
+-----------------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'eventCal'@'localhost' IDENTIFIED BY PASSWORD '*xxxx' |
| GRANT ALL PRIVILEGES ON `tmp`.* TO 'eventCal'@'localhost'                                                       |
| GRANT ALL PRIVILEGES ON `eventCalTesting`.* TO 'eventCal'@'localhost'                                           |
| GRANT ALL PRIVILEGES ON `eventCal`.* TO 'eventCal'@'localhost'                                                  |
| GRANT ALL PRIVILEGES ON `eventCal_categoryMigration`.* TO 'eventCal'@'localhost'                                |
+-----------------------------------------------------------------------------------------------------------------+
5 rows in set (0.00 sec)

mysql> select hex(LOAD_FILE('/home/jlam/code/projectName/doc/filesForTesting/images/imageTest01.jpg'));
+-------------------------------------------------------------------------------------------------------------+
| hex(LOAD_FILE('/home/jlam/code/projectName/doc/filesForTesting/images/imageTest01.jpg')) |
+-------------------------------------------------------------------------------------------------------------+
| NULL                                                                                                        |
+-------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

In other root session:


mysql> grant file ON *.*  to eventCal@localhost;
Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

Back in user session, I still can't load the file


mysql> select hex(LOAD_FILE('/home/jlam/code/projectName/doc/filesForTesting/images/imageTest01.jpg'));
+-------------------------------------------------------------------------------------------------------------+
| hex(LOAD_FILE('/home/jlam/code/projectName/doc/filesForTesting/images/imageTest01.jpg')) |
+-------------------------------------------------------------------------------------------------------------+
| NULL                                                                                                        |
+-------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

.....But if I log out and back in:


mysql> exit
Bye

16:40:14 (getImages) ~/code/projectName/doc/filesForTesting/images$ mysql -u eventCal -p eventCal
Enter password: 

mysql> select hex(LOAD_FILE('/home/jlam/code/projectName/doc/filesForTesting/images/imageTest01.jpg'));
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| hex(LOAD_FILE('/home/jlam/code/projectName/doc/filesForTesting/images/imageTest01.jpg'))                                                                                                                                
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| FFD8FFE1001845786966000049492A00080000000000000000000000FFEC00114475636B7900010004000000500000FFE10407687474703A2F2F6E732E61646F62652E636F6D2F7861702F312E302F003C3F787061636B657420626567696E3D22EFBBBF222069643D2257354D304D7043656869487
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

MySQL LOAD_FILE() loads null values

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