| Bug #81099 | INNODB_METRICS need better testing | ||
|---|---|---|---|
| Submitted: | 15 Apr 2016 15:02 | Modified: | 18 Apr 2016 6:42 |
| Reporter: | Peter Zaitsev | Email Updates: | |
| Status: | Verified | Impact on me: | |
| Category: | MySQL Server: InnoDB storage engine | Severity: | S3 (Non-critical) |
| Version: | 5.7, 5.6.30, 5.7.12 | OS: | Any |
| Assigned to: | CPU Architecture: | Any | |
[15 Apr 2016 17:06]
MySQL Verification Team
also: https://bugs.mysql.com/bug.php?id=73114
[15 Apr 2016 18:48]
Laurynas Biveinis
Also: http://bugs.mysql.com/bug.php?id=77399 "Deadlocks missed by INFORMATION_SCHEMA.INNODB_METRICS lock_deadlocks counter"
[18 Apr 2016 6:42]
MySQL Verification Team
Hello Peter, Thank you for the report. Observed reported issue with 5.6.30, 5.7.12 GA builds(also, on 5.7/5.8 daily builds). Keeping this report independent of Shane's/Laurynas's for the fix + to implement test functionalities for the affected metrics. Regards, Umesh
[18 Apr 2016 6:43]
MySQL Verification Team
test results
Attachment: 81099.results (application/octet-stream, text), 6.70 KiB.
Description: Right now enabling all Innodb Metrics and running basic sysbench with them I see many of them are badly wrong: mysql> select name,count from innodb_metrics where name like "trx_%"; +---------------------------+--------+ | name | count | +---------------------------+--------+ | trx_rw_commits | 253526 | | trx_ro_commits | 5 | | trx_nl_ro_commits | 3 | | trx_commits_insert_update | 251132 | | trx_rollbacks | 0 | | trx_rollbacks_savepoint | 0 | | trx_rollback_active | 0 | | trx_active_transactions | -9939 | | trx_rseg_history_len | 53047 | | trx_undo_slots_used | -133 | | trx_undo_slots_cached | -1682 | | trx_rseg_current_size | 1306 | +---------------------------+--------+ 12 rows in set (0.00 sec) Ie trx_active_transactions can't be negative. Furthermore it looks like type is incorrect for number of counters. This one is named "counter" while it looks like it is gauge: mysql> select * from innodb_metrics where name='trx_active_transactions' \G *************************** 1. row *************************** NAME: trx_active_transactions SUBSYSTEM: transaction COUNT: -110751 MAX_COUNT: 64 MIN_COUNT: -110751 AVG_COUNT: -0.2537919497691259 COUNT_RESET: -110751 MAX_COUNT_RESET: 64 MIN_COUNT_RESET: -110751 AVG_COUNT_RESET: NULL TIME_ENABLED: 2016-04-10 09:47:06 TIME_DISABLED: NULL TIME_ELAPSED: 436385 TIME_RESET: NULL STATUS: enabled TYPE: counter COMMENT: Number of active transactions 1 row in set (0.00 sec) How to repeat: sysbench --test=/usr/share/doc/sysbench/tests/db/oltp.lua --oltp-table-size=500000 --max-time=0 --oltp-read-only=off --max-requests=0 --num-threads=64 --rand-type=pareto --db-driver=mysql --mysql-password=password --mysql-db=test_innodb run Suggested fix: Fix the issue but also implement some basic test functionality for those metrics otherwise they will very likely to break with code updates.