Merge pull request #10 from jmrenouard/feature/cpu-aware-innodb-instances

Improve innodb_buffer_pool_instances recommendation

Author: jmrenouard

mysqltuner.pl

@@ -5933,7 +5933,7 @@ sub mariadb_xtradb {
     infoprint "XtraDB is enabled.";
     infoprint "Note that MariaDB 10.2 makes use of InnoDB, not XtraDB."
 
-      # Not implemented
+    # Not implemented
 }
 
 # Recommendations for RocksDB
@@ -6762,6 +6762,15 @@ sub mysql_innodb {
             #  InnoDB Buffer Pool Size > 64Go
             my $max_innodb_buffer_pool_instances =
               int( $myvar{'innodb_buffer_pool_size'} / ( 1024 * 1024 * 1024 ) );
+
+            my $nb_cpus = cpu_cores();
+            if ( $nb_cpus > 0 && $max_innodb_buffer_pool_instances > $nb_cpus )
+            {
+                infoprint
+"Recommendation for innodb_buffer_pool_instances is capped by the number of CPU cores ($nb_cpus).";
+                $max_innodb_buffer_pool_instances = $nb_cpus;
+            }
+
             $max_innodb_buffer_pool_instances = 64
               if ( $max_innodb_buffer_pool_instances > 64 );
 
@@ -6803,7 +6812,7 @@ sub mysql_innodb {
         infoprint
 "innodb_buffer_pool_chunk_size is set to 'autosize' (0) in MariaDB >= 10.8. Skipping chunk size checks.";
     }
-    elsif (!defined( $myvar{'innodb_buffer_pool_chunk_size'} )
+    elsif ( !defined( $myvar{'innodb_buffer_pool_chunk_size'} )
         || $myvar{'innodb_buffer_pool_chunk_size'} == 0
         || !defined( $myvar{'innodb_buffer_pool_size'} )
         || $myvar{'innodb_buffer_pool_size'} == 0
@@ -7635,15 +7644,17 @@ sub dump_result {
         }
 
         my $json = JSON->new->allow_nonref;
-        print $json->utf8(1)->pretty( ( $opt{'prettyjson'} ? 1 : 0 ) )
+        print $json->utf8(1)
+          ->pretty( ( $opt{'prettyjson'} ? 1 : 0 ) )
           ->encode( \%result );
 
         if ( $opt{'outputfile'} ne 0 ) {
             unlink $opt{'outputfile'} if ( -e $opt{'outputfile'} );
             open my $fh, q(>), $opt{'outputfile'}
               or die
 "Unable to open $opt{'outputfile'} in write mode. please check permissions for this file or directory";
-            print $fh $json->utf8(1)->pretty( ( $opt{'prettyjson'} ? 1 : 0 ) )
+            print $fh $json->utf8(1)
+              ->pretty( ( $opt{'prettyjson'} ? 1 : 0 ) )
               ->encode( \%result );
             close $fh;
         }