Invalid argument supplied for foreach - Error establishing a database connection

Question

I am having an issue with my Virtual Private server. The VPS hosts 2 wordpress websites. Since last week the server suddenly started to generate errors sometimes and both websites show the error below on the front-end. After restarting the Apache webserver it would be OK again for 1 or 2 days, but this time seems to be decreasing.

The error which is generated at the front-end is:

"Warning: Invalid argument supplied for foreach() in /var/www/html/domainname/wp-includes/locale.php on line 117 Warning: Invalid argument supplied for foreach() in /var/www/html/domainname/wp-includes/locale.php on line 159 Error establishing a database connection"

Contents of Locale.php: (nothing has been changed to this)

function init() {
    // The Weekdays
    $this->weekday[0] = /* translators: weekday */ __('Sunday');
    $this->weekday[1] = /* translators: weekday */ __('Monday');
    $this->weekday[2] = /* translators: weekday */ __('Tuesday');
    $this->weekday[3] = /* translators: weekday */ __('Wednesday');
    $this->weekday[4] = /* translators: weekday */ __('Thursday');
    $this->weekday[5] = /* translators: weekday */ __('Friday');
    $this->weekday[6] = /* translators: weekday */ __('Saturday');

    // The first letter of each day. The _%day%_initial suffix is a hack to make
    // sure the day initials are unique.
    $this->weekday_initial[__('Sunday')]    = /* translators: one-letter abbreviation of the weekday */ __('S_Sunday_initial');
    $this->weekday_initial[__('Monday')]    = /* translators: one-letter abbreviation of the weekday */ __('M_Monday_initial');
    $this->weekday_initial[__('Tuesday')]   = /* translators: one-letter abbreviation of the weekday */ __('T_Tuesday_initial');
    $this->weekday_initial[__('Wednesday')] = /* translators: one-letter abbreviation of the weekday */ __('W_Wednesday_initial');
    $this->weekday_initial[__('Thursday')]  = /* translators: one-letter abbreviation of the weekday */ __('T_Thursday_initial');
    $this->weekday_initial[__('Friday')]    = /* translators: one-letter abbreviation of the weekday */ __('F_Friday_initial');
    $this->weekday_initial[__('Saturday')]  = /* translators: one-letter abbreviation of the weekday */ __('S_Saturday_initial');

    foreach ($this->weekday_initial as $weekday_ => $weekday_initial_) {
        $this->weekday_initial[$weekday_] = preg_replace('/_.+_initial$/', '', $weekday_initial_);
    }

    // Abbreviations for each day.
    $this->weekday_abbrev[__('Sunday')]    = /* translators: three-letter abbreviation of the weekday */ __('Sun');
    $this->weekday_abbrev[__('Monday')]    = /* translators: three-letter abbreviation of the weekday */ __('Mon');
    $this->weekday_abbrev[__('Tuesday')]   = /* translators: three-letter abbreviation of the weekday */ __('Tue');
    $this->weekday_abbrev[__('Wednesday')] = /* translators: three-letter abbreviation of the weekday */ __('Wed');
    $this->weekday_abbrev[__('Thursday')]  = /* translators: three-letter abbreviation of the weekday */ __('Thu');
    $this->weekday_abbrev[__('Friday')]    = /* translators: three-letter abbreviation of the weekday */ __('Fri');
    $this->weekday_abbrev[__('Saturday')]  = /* translators: three-letter abbreviation of the weekday */ __('Sat');

    // The Months
    $this->month['01'] = /* translators: month name */ __('January');
    $this->month['02'] = /* translators: month name */ __('February');
    $this->month['03'] = /* translators: month name */ __('March');
    $this->month['04'] = /* translators: month name */ __('April');
    $this->month['05'] = /* translators: month name */ __('May');
    $this->month['06'] = /* translators: month name */ __('June');
    $this->month['07'] = /* translators: month name */ __('July');
    $this->month['08'] = /* translators: month name */ __('August');
    $this->month['09'] = /* translators: month name */ __('September');
    $this->month['10'] = /* translators: month name */ __('October');
    $this->month['11'] = /* translators: month name */ __('November');
    $this->month['12'] = /* translators: month name */ __('December');

    // Abbreviations for each month. Uses the same hack as above to get around the
    // 'May' duplication.
    $this->month_abbrev[__('January')] = /* translators: three-letter abbreviation of the month */ __('Jan_January_abbreviation');
    $this->month_abbrev[__('February')] = /* translators: three-letter abbreviation of the month */ __('Feb_February_abbreviation');
    $this->month_abbrev[__('March')] = /* translators: three-letter abbreviation of the month */ __('Mar_March_abbreviation');
    $this->month_abbrev[__('April')] = /* translators: three-letter abbreviation of the month */ __('Apr_April_abbreviation');
    $this->month_abbrev[__('May')] = /* translators: three-letter abbreviation of the month */ __('May_May_abbreviation');
    $this->month_abbrev[__('June')] = /* translators: three-letter abbreviation of the month */ __('Jun_June_abbreviation');
    $this->month_abbrev[__('July')] = /* translators: three-letter abbreviation of the month */ __('Jul_July_abbreviation');
    $this->month_abbrev[__('August')] = /* translators: three-letter abbreviation of the month */ __('Aug_August_abbreviation');
    $this->month_abbrev[__('September')] = /* translators: three-letter abbreviation of the month */ __('Sep_September_abbreviation');
    $this->month_abbrev[__('October')] = /* translators: three-letter abbreviation of the month */ __('Oct_October_abbreviation');
    $this->month_abbrev[__('November')] = /* translators: three-letter abbreviation of the month */ __('Nov_November_abbreviation');
    $this->month_abbrev[__('December')] = /* translators: three-letter abbreviation of the month */ __('Dec_December_abbreviation');

    foreach ($this->month_abbrev as $month_ => $month_abbrev_) {
        $this->month_abbrev[$month_] = preg_replace('/_.+_abbreviation$/', '', $month_abbrev_);
    }

I did not change anything in the php or mysql configuration, I have no clue why it has started behaving like this.

A temporary solution is to restart the httpd service, then everything would be fine for about 1 day, but it seems this time is decreasing to sometimes half of an hour.

At first I was thinking this issue is caused by Mysql. However, I configured a test tool to test mysql. At moments the VPS is suffering the issue, there is not a problem logging in into the database via the Mysql testtool.

To be honest, I am no php guru, hopefully somebody can put me on the right track. I've been troubleshooting and browsing forums by myself for some hours now, but I just don't now how to solve it.

If you need more info, please ask. Many thanks in advance.

Best regards, Robert

Answer 1

Try to check them for is they are array or not before for loop like

 if(is_array($this->weekday_initial))
     foreach ($this->weekday_initial as $weekday_ => $weekday_initial_)