From dd9914be88fdb8abdf72d336a126ae99e4b4b83b Mon Sep 17 00:00:00 2001
From: Jean-Marie Renouard <jmrenouard@gmail.com>
Date: Fri, 11 Mar 2022 09:42:01 +0100
Subject: [PATCH] False impression on key buffer usage #573

---
 mysqltuner.pl | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/mysqltuner.pl b/mysqltuner.pl
index 821b777..7ddb2ef 100755
--- a/mysqltuner.pl
+++ b/mysqltuner.pl
@@ -3587,6 +3587,13 @@ sub mysql_myisam {
         infoprint "MyISAM Metrics are disabled on last MySQL versions.";
         return;
     }
+    my $nb_myisam_tables=select_one(
+"SELECT COUNT(*) FROM information_schema.TABLES WHERE ENGINE='MyISAM'"
+              );
+    if ( $nb_myisam_tables == 0 ) {
+        infoprint "No MyISAM table(s) detected ....";
+        return;
+    }
 
     # Key buffer usage
     if ( $mycalc{'pct_key_buffer_used'} > 0 ) {