PDOException: SQLSTATE[HY000]: General error: 3 Error writing file ‘/tmp/MYHKgYpv’ (Errcode: 28)

I have installed Visitor Module Drupal 7. I have viewed the reports using www.domain.com/visitors. All the reports are working well. But when i view the user activity report it shows below error.

PDOException: SQLSTATE[HY000]: General error: 3 Error writing file ‘/tmp/MYHKgYpv’ (Errcode: 28): SELECT u.name AS name, u.uid AS uid, COUNT(DISTINCT v.visitors_id) AS hits, COUNT(DISTINCT n.nid) AS nodes, COUNT(DISTINCT c.cid) AS comments FROM {users} u LEFT OUTER JOIN {visitors} v ON u.uid=v.visitors_uid LEFT OUTER JOIN {node} n ON u.uid=n.uid LEFT OUTER JOIN {comment} c ON u.uid=c.uid WHERE (visitors_date_time BETWEEN :db_condition_placeholder_0 AND :db_condition_placeholder_1) GROUP BY u.name, u.uid, v.visitors_uid, n.uid, c.uid ORDER BY hits DESC LIMIT 10 OFFSET 0; Array ( [:db_condition_placeholder_0] => 1451606400 [:db_condition_placeholder_1] => 1452556799 ) in PagerDefault->execute() (line 79 of /home/legalmon/public_html/includes/pager.inc).

How can i fix this issue?

Answer

You should continuously check your /tmp folder size while triggering “USER REPORT Query”.

If /tmp directory is 100% utilized you would experience this error.

Solution is to mount some GB’s to /tmp directory or set new location of MySQL tmp.

To setting up New location:

Create a directory anywhere you have enough space(can be the "/" root directory)

# mkdir /home/mysqltmp

Give write permissions

# chmod 1777 /home/mysqltmp

Open MY.CNF File

# /etc/my.cnf 

Add below line under the [mysqld] section and save the file

# tmpdir=/home/mysqltmp

Restart MySQL

# /etc/init.d/mysql restart

Check new location

# mysqladmin var | grep tmpdir

This should show following return.

| slave_load_tmpdir                       | /home/mysqltmp
| tmpdir                                  | /home/mysqltmp

Done !!

Try refresh the Page.