Fix/26 (#39)

* Fixed lock count collect

I found bug on your source.
You do not need to plus 1 when  while syntax after add "group by"
If you want get correct number need use count

* add a CHANGELOG entry

Author: majormoses

CHANGELOG.md

@@ -5,6 +5,9 @@ This CHANGELOG follows the format listed [here](https://github.com/sensu-plugins
 
 ## [Unreleased]
 
+### Fixed
+- metric-postgres-locks.rb: Fixed lock count collect (@madboxkr)
+
 ## [1.4.1] - 2017-09-26
 ### Fixed
 - metrics-postgres-query.rb: Add a nil check to avoid failure when the query result is empty (@eheydrick)

bin/metric-postgres-locks.rb

@@ -90,15 +90,15 @@ def run
                          port: config[:port],
                          connect_timeout: config[:timeout])
     request = [
-      'SELECT mode, count(mode) FROM pg_locks',
-      "where database = (select oid from pg_database where datname = '#{config[:database]}')",
-      'group by mode'
+      'SELECT mode, count(mode) AS count FROM pg_locks',
+      "WHERE database = (SELECT oid FROM pg_database WHERE datname = '#{config[:database]}')",
+      'GROUP BY mode'
     ]
 
     con.exec(request.join(' ')) do |result|
       result.each do |row|
         lock_name = row['mode'].downcase.to_sym
-        locks_per_type[lock_name] += 1
+        locks_per_type[lock_name] = row['count']
       end
     end