精致的參數(shù) - max_binlog_files

max_binlog_files，是Percona MySQL分支提供的限制binlog文件數(shù)量的參數(shù)，在刪除歸檔數(shù)據(jù)、binlog增長(zhǎng)很快的情況下，很實(shí)用的一個(gè)參數(shù)。

該參數(shù)也對(duì)正在被使用的binlog提供了保護(hù)，是purge不掉的，如下。

[root@mysql.sock][(none)]>purge binary logs to 'bin.016222';

Query OK, 0 rows affected, 1 warning (0.01 sec)

[root@mysql.sock][(none)]>>show warnings;

+---------+------+------------------------------------------------------------------------------------------------------+

| Level? ?| Code | Message? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? |

+---------+------+------------------------------------------------------------------------------------------------------+

| Warning | 1867 | file ./bin.016215 was not purged because it was being read by 1 thread(s), purged only 0 out of 7 files. |

+---------+------+------------------------------------------------------------------------------------------------------+

1 row in set (0.00 sec)

$ perror 1867

MySQL error code 1867 (ER_WARN_PURGE_LOG_IN_USE): file %s was not purged because it was being read by %d thread(s), purged only %d out of %d files.

error日志中也是用體現(xiàn)的。

2019-09-18T01:02:56.643574+08:00 10326541 [Warning] file ./bin.016215 was not purged because it was being readby thread number 17218543

2019-09-18T01:03:18.196285+08:00 17244031 [Warning] file ./bin.016215 was not purged because it was being readby thread number 17218543