Bug #80756 Innodb status always prints `spins` with 0

• Submitted: 16 Mar 2016 3:22
• Modified: 23 Mar 2016 12:56
• Reporter: KENTARO KATO
• Status: Verified
• Category: MySQL Server: InnoDB storage engine
• Severity: S3 (Non-critical)
• Version: 5.7.11
• OS: Any
• CPU Architecture: Any

[16 Mar 2016 3:22] KENTARO KATO

Description:
Description:
As of MySQL 5.7.9, SEMAPHORES section of SHOW ENGINE INNODB STATUS always prints `spins` with 0.
The spins of RW-shared and RW-excl is always 0.
The spins of RW-sx is correct value.
I expected `SHOW ENGINE INNODB STATUS` prints `spins` with correct value like RW-sx line.

Example.
mysql> SHOW ENGINE INNODB STATUS\G
----------
SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 11239790
OS WAIT ARRAY INFO: signal count 5047801
RW-shared spins 0, rounds 10972038, OS waits 5874008
RW-excl spins 0, rounds 160819717, OS waits 4858536
RW-sx spins 394761, rounds 6462659, OS waits 75010
Spin rounds per wait: 10972038.00 RW-shared, 160819717.00 RW-excl, 16.37 RW-sx

Environment.
MySQL version: 5.7.11
OS: Ubuntu 14.04, Linux 3.13.0-67

https://github.com/mysql/mysql-server/commit/f0b64bcc9b37a44ed209283f57357d2826fa65ea#diff...
It seems that adding spin_wait_count is deleted.

How to repeat:
Run sysbench(--test=oltp) and SHOW ENGINE INNODB STATUS.

Suggested fix:
increment spin_wait_count ?

[23 Mar 2016 12:56] MySQL Verification Team

Hello Kentaro Kato,

Thank you for the report.
Observed this with 5.7.11(5.7.13 daily build as well) build.

Thanks,
Umesh

[23 Mar 2016 12:57] MySQL Verification Team

-- 5.7.13 daily build

----------
SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 7145684
OS WAIT ARRAY INFO: signal count 3887118
RW-shared spins 0, rounds 14230949, OS waits 5379568
RW-excl spins 0, rounds 47535687, OS waits 1406098
RW-sx spins 4547, rounds 130004, OS waits 3724
Spin rounds per wait: 14230949.00 RW-shared, 47535687.00 RW-excl, 28.59 RW-sx
------------------------