分类： Mysql/postgreSQL
2009-11-01 16:23:46
Recap: this information can be useful if you’re looking for a good innodb_log_file_size value, such that will not pose too much I/O (smaller values will make for more frequent flushes), not will make for a too long recovery time (larger values mean more transactions to recover upon crash).
It is assumed that the 60 seconds period represents an average system load, not some activity spike period. Edit the sleep time and factors as you will to sample longer or shorter periods.
SELECT
innodb_os_log_written_per_minute*60
AS estimated_innodb_os_log_written_per_hour,
CONCAT(ROUND(innodb_os_log_written_per_minute*60/1024/1024, 1), 'MB')
AS estimated_innodb_os_log_written_per_hour_mb
FROM
(SELECT SUM(value) AS innodb_os_log_written_per_minute FROM (
SELECT -VARIABLE_VALUE AS value
FROM INFORMATION_SCHEMA.GLOBAL_STATUS
WHERE VARIABLE_NAME = 'innodb_os_log_written'
UNION ALL
SELECT SLEEP(60)
FROM DUAL
UNION ALL
SELECT VARIABLE_VALUE
FROM INFORMATION_SCHEMA.GLOBAL_STATUS
WHERE VARIABLE_NAME = 'innodb_os_log_written'
) s1
) s2
;
Sample output:
+------------------------------------------+---------------------------------------------+
| estimated_innodb_os_log_written_per_hour | estimated_innodb_os_log_written_per_hour_mb |
+------------------------------------------+---------------------------------------------+
| 584171520 | 557.1MB |
+------------------------------------------+---------------------------------------------+
