Editing Troubleshooting of MySQL errors (section)

=== Error!: SQLSTATE[HY000]: General error: 3 Error writing file xxx.tmp (Errcode: 28 - No space left on device) ===

Example error message: Error!: SQLSTATE[HY000]: General error: 3 Error writing file 'C:\Windows\SERVIC~2\NETWOR~1\AppData\Local\Temp\MY2713.tmp' (Errcode: 28 - No space left on device)

Condition: Check the disk free space of mysql {{kbd | key=tmpdir}} folder

Solutions: Increase the free space of mysql {{kbd | key=tmpdir}} folder. Or change the mysql {{kbd | key=tmpdir}} folder with another hard disk drive contains more free space<ref>[https://stackoverflow.com/questions/11990887/changing-the-tmp-folder-of-mysql Changing the tmp folder of mysql - Stack Overflow]</ref>.
* Check the current mysql {{kbd | key=tmpdir}} folder. Query the syntax {{kbd | key=<nowiki>SHOW VARIABLES LIKE 'tmpdir';</nowiki>}}.
** On {{Win}} the default temporary folder<ref>[https://answers.microsoft.com/en-us/windows/forum/windows_7-windows_programs/where-is-the-temporary-folder/44a039a5-45ba-48dd-84db-fd700e54fd56 Where is the Temporary folder? - Microsoft Community]</ref> is {{kbd | key=<nowiki>%TMP%</nowiki>}} = {{kbd | key=<nowiki>%USERPROFILE%\AppData\Local\Temp</nowiki>}}. 
** On {{Linux}} the default temporary folder maybe is {{kbd | key=<nowiki>/tmp</nowiki>}}
* Edit the [https://dev.mysql.com/doc/refman/5.7/en/option-files.html mysql configuration file]
<pre>
[mysqld]
tmpdir=X:/temp
</pre>
* Restart the MySQL service

Validation
* Query the syntax {{kbd | key=<nowiki>SHOW VARIABLES LIKE 'tmpdir';</nowiki>}} to validate the modification of mysql configuration file.