InnoDB monitor reads in data pages needlessly

[Laurynas Biveinis]

XtraDB introduces innodb_show_verbose_locks option. When it's 0 (the default), the detailed lock info is omitted from the InnoDB monitor output. But the relevant data pages are still being read in by lock_print_info_all_transactions():

   lock_mutex_exit_kernel();

   mtr_start(&mtr);

   buf_page_get_gen(space, zip_size, page_no, RW_NO_LATCH,
      NULL, BUF_GET_POSSIBLY_FREED,
      __FILE__, __LINE__, &mtr);

   mtr_commit(&mtr);

   load_page_first = FALSE;

   lock_mutex_enter_kernel();

This snippet-except for kernel mutex ops-should be guarded by if (srv_show_verbose_locks) check.

[Laurynas Biveinis (laurynas-biveinis)]

5.1 affected too.

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-1301