MySQL 5.5 provides improved access to execution and
performance information. Diagnostic improvements include Dtrace
probes, expanded
SHOW ENGINE INNODB
STATUS output, and a new status variable.
DTrace Support
MySQL 5.5 includes support for DTrace. The DTrace probes work on Solaris, Mac OS X, and FreeBSD. For information on using DTrace in MySQL, see Section 5.7, “Tracing mysqld Using DTrace”.
Enhanced
SHOW ENGINE INNODB
STATUS Output
The output from
SHOW ENGINE INNODB
STATUS includes more information due to changes made
for InnoDB Plugin. A description of revisions
to statement output follows.
A new BACKGROUND THREAD section has
srv_master_thread lines that show work done
by the main background thread.
---------- BACKGROUND THREAD ---------- srv_master_thread loops: 53 1_second, 44 sleeps, 5 10_second, 7 background, 7 flush srv_master_thread log flush and writes: 48
The SEMAPHORES section includes a line to
show the number of spinlock rounds per OS wait for a mutex.
---------- SEMAPHORES ---------- ... Spin rounds per wait: 0.00 mutex, 20.00 RW-shared, 0.00 RW-excl
New Status Variable
The
Innodb_have_atomic_builtins
status variable provides information about availability of
atomic instructions; see Section 1.5.1, “Scalability Improvements”.