add sleep to pt-mysql-summary

dump-server-state.sh

@@ -752,7 +752,10 @@ task_mysql_summary() {
         # Look for local MySQL or MariaDB process
         if pgrep mysqld > /dev/null || pgrep mariadbd > /dev/null; then
             if ${mysqladmin_bin} ping > /dev/null 2>&1; then
-                ${pt_mysql_summary_bin} > "${dump_dir}/mysql-summary.txt" 2> "${dump_dir}/mysql-summary.err"
+                # important to set sleep to 0
+                # because we don't want to block
+                # even if we lose some insight.
+                ${pt_mysql_summary_bin} --sleep 0 > "${dump_dir}/mysql-summary.txt" 2> "${dump_dir}/mysql-summary.err"
                 last_rc=$?
 
                 if [ ${last_rc} -eq 0 ]; then