From 70687a62be9f9264af50d428d023320c09f23a02 Mon Sep 17 00:00:00 2001
From: root <jmrenouard@gmail.com>
Date: Thu, 2 Jul 2015 16:42:53 +0200
Subject: [PATCH] Adding metrics on worst selectivity index and unused indexes
 --idxstat option is needed to activate this features

---
 mysqltuner.pl | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/mysqltuner.pl b/mysqltuner.pl
index d0402f5..fdaaf31 100755
--- a/mysqltuner.pl
+++ b/mysqltuner.pl
@@ -1466,7 +1466,30 @@ ENDSQL
 		infoprint " +-- CARDINALITY : ".$info[4]." distinct values\n";
 		infoprint " +-- NB ROWS     : ".$info[5]." rows\n";
 		infoprint " +-- SELECTIVITY : ".$info[6]."%\n";
+		if ($info[6] < 25) {
+			badprint "$info[1] has a low selectivity\n";
+		}
 	}
+
+	return unless (defined($myvar{'performance_schema'}) and $myvar{'performance_schema'} eq 'ON' );
+
+$selIdxReq= <<'ENDSQL';
+SELECT CONCAT(CONCAT(object_schema,'.'),object_name) AS 'table', index_name 
+FROM performance_schema.table_io_waits_summary_by_index_usage
+WHERE index_name IS NOT NULL
+AND count_star =0  
+AND index_name <> 'PRIMARY' 
+AND object_schema != 'mysql' 
+ORDER BY count_star, object_schema, object_name;
+ENDSQL
+	@idxinfo=select_array($selIdxReq);
+	infoprint "Unsused indexes:\n";
+	push(@generalrec, "Remove unused indexes.") if (scalar(@idxinfo)>0);
+	foreach (@idxinfo) {
+		debugprint "$_\n";
+		my @info= split /\s/;
+		badprint "Index: $info[1] on $info[0] is not used.\n";
+	}	
 }
 # Take the two recommendation arrays and display them at the end of the output
 sub make_recommendations {