Default site search broken when entered blank spaces as search keyword

Hi,

Currently site search results in an fatal error when blank spaces entered under search text box (appearing on the top right corner). I have installed latest version of commons 7.x-3.23 and getting this error. Please help me to resolve this, due to this issue I can not push the site live.

Below are current search settings enabled and site is indexed 100%,

* Minimum word length to index : 3
* Active search modules : Faceted Navigation for Search, Node, User
* Default search module : Node

Below is the error message:

You must include at least one positive keyword with 3 characters or more.
PDOException: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'IS NULL ) GROUP BY i.type, i.sid HAVING (COUNT(*) >= '0') ) r GROUP BY r.value' at line 4: SELECT r.value AS value, COUNT(r.value) AS count FROM (SELECT n.changed AS value FROM {search_index} i INNER JOIN {node} n ON n.nid = i.sid INNER JOIN {search_total} t ON i.word = t.word INNER JOIN {search_dataset} d ON i.sid = d.sid AND i.type = d.type WHERE (n.status = :db_condition_placeholder_0) AND (n.changed >= :db_condition_placeholder_1) AND (n.changed < :db_condition_placeholder_2) AND (i.type = :db_condition_placeholder_3) AND ( IS NULL ) GROUP BY i.type, i.sid HAVING (COUNT(*) >= :matches) ) r GROUP BY r.value ORDER BY count DESC; Array ( [:db_condition_placeholder_0] => 1 [:db_condition_placeholder_1] => 1427176268 [:db_condition_placeholder_2] => 1427266268 [:db_condition_placeholder_3] => node [:matches] => 0 ) in FacetapiFacetProcessor->initializeBuild() (line 1482 of /var/www/commons/profiles/commons/modules/contrib/facetapi/plugins/facetapi/adapter.inc)

Thanks.