我对 MySQL (5.5.59) 有一个奇怪的问题：
我有一个日志数据库（我存储供应商请求的原始数据）。此表已压缩：
CREATE TABLE `logs` (
`id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`idLogType` tinyint(3) unsigned NOT NULL,
`idAccount` mediumint(8) unsigned NOT NULL,
(...)
`message` text NOT NULL,
`date` datetime NOT NULL,
PRIMARY KEY (`id`),
KEY `LOGTYPE` (`idLogType`),
KEY `ACCOUNT` (`idAccount`),
) ENGINE=InnoDB AUTO_INCREMENT=(...) DEFAULT CHARSET=utf8 ROW_FORMAT=COMPRESSED KEY_BLOCK_SIZE=8
我的目标是通过删除旧记录并重建表来清理这张表。因为它是一张大桌子，所以我使用了 pt-online-schema-change 和 Oak-chunk-update 来完成这项工作。
我使用https://shlomi-noach.github.io/openarkkit/oak-chunk-update.html删除了所有去年的旧记录
然后我执行表的重建以释放可用空间（启用了 innodb_file_per_table
pt-online-schema-change
--alter "ENGINE=InnoDB"
--nocheck-replication-filters --execute --statistics --progress=percentage,1
--set-vars='lock_wait_timeout=60' --check-alter
--no-swap-tables --no-drop-triggers --no-drop-old-table --no-drop-new-table
--chunk-time=1 --chunk-size=20 --new-table-name='__new_logs'
h=**HOST_#########**,D=DB_#########,t=logs,u=root --ask-pass
（重点是 --alter 语句）
所以现在，我有 2 张桌子：
- 日志（原始的）
- __new_logs 新日志（优化）
但它们在结构上并不相同：
SELECT TABLE_NAME, ENGINE, ROW_FORMAT, CREATE_OPTIONS
FROM information_schema.tables
WHERE
ENGINE = 'innodb' AND TABLE_NAME LIKE '%logs'
返回此结果：
'TABLE_NAME' 'ENGINE' 'ROW_FORMAT' 'CREATE_OPTIONS',
'__new_logs' 'InnoDB' 'Compact' 'row_format=COMPRESSED KEY_BLOCK_SIZE=8',
'logs' 'InnoDB' 'Compressed' 'row_format=COMPRESSED KEY_BLOCK_SIZE=8',
Why the table __new_logs is flagged "compact" and not compressed, but still has "create options" set to row_format=COMPRESSED KEY_BLOCK_SIZE=8
A show create table of the __new_logs table shows:
CREATE TABLE `__new_logs` (
`id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`idLogType` tinyint(3) unsigned NOT NULL,
`idAccount` mediumint(8) unsigned NOT NULL,
(...)
`message` text NOT NULL,
`date` datetime NOT NULL,
PRIMARY KEY (`id`),
KEY `LOGTYPE` (`idLogType`),
KEY `ACCOUNT` (`idAccount`),
) ENGINE=InnoDB AUTO_INCREMENT=(...) DEFAULT CHARSET=utf8 ROW_FORMAT=COMPRESSED KEY_BLOCK_SIZE=8
So it is still marked as compressed.
Last strange thing, the table __new_logs is bigger than the original logs table... I feel like the compression is not really done on this new table...