Since few days I've got the following error message in my Server error log :
www.xxx.com [client XXX.XXX.XXX.XXX] rdbmmap (21): rdbm_fetch failed (1)
Although the site is loading right. I would like to know about this error. Can't find anything around. Does anybody know about this?
Server configuration :
Server-Info: Apache/2.2.31 (Unix)
PHP-Version: 7.1.8
WordPress: 4.8.1
MySQL-Version: 5.6.37
Thanks in advance.