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HomeDatabaseMysql Tutorial如何修复MySQL数据库表

一张损坏的表的症状通常是查询意外中断并且你能看到例如这些错误: “tbl_name.frm”被锁定不能改变。 不能找到文件“tbl_name.MYI”(Errcode :### )。 从表处理器的得到错误###(此时,错误135是一个例外)。 意外的文件结束。 记录文件被毁坏。 在这些情

  一张损坏的表的症状通常是查询意外中断并且你能看到例如这些错误:
   “tbl_name.frm”被锁定不能改变。
   不能找到文件“tbl_name.MYI”(Errcode :### )。
   从表处理器的得到错误###(此时,错误135是一个例外)。
   意外的文件结束。
   记录文件被毁坏。
  在这些情况下,你必须修复表。表的修复是一项非常困难的工作,很多情况下令人束手无策。然而,有一些常规的知道思想和过程,可以遵循它们来增加修正表的机会。通常,开始是可以用最快的修复方法,看看能否袖珍故障。如果发现不成功,可以逐步升级到更彻底的但更慢的修复方法。如果仍旧难以修复,就应该从备份中恢复了。在上一章已经详细介绍了这一部分内容。
  简单安全的修复
  为了修复一个表执行下列步骤:
   首先,用--recover,-r选项修正表,并且用--quick,-q选项,来只根据索引文件的内容进行恢复。这样不接触数据文件来修复索引文件。(-r意味着“恢复模式”)
  myisamchk -r -q tbl_nameisamchk -r -q tbl_name
   如果问题仍旧存在,则忽略--quick选项,允许修复程序修改数据文件,因为这可能存在问题。下面的命令将从数据文件中删除不正确的记录和已被删除的记录并重建索引文件:
  myisamchk -r tbl_nameisamchk -r tbl_name
   如果前面的步骤失败,使用。安全恢复模式使用一个老的恢复方法,处理常规恢复模式不行的少数情况(但是更慢)。
  myisamchk --safe-recover tbl_nameisamchk --safe-recover tbl_name
  困难的修理
  如果在索引文件的第一个16K块被破坏,或包含不正确的信息,或如果索引文件丢失,你只应该到这个阶段 。在这种情况下,创建一个新的索引文件是必要的。按如下这样的步骤做:
   定位到包含崩溃表的数据库目录中
   把数据文件移更安全的地方。
   使用表描述文件创建新的(空)数据和索引文件:
  shell> mysql db_namemysql> DELETE FROM tbl_name;mysql> quit
  上述语句将重新创建新的空表,并使用表的的描述文件tbl_name.frm重新生成新的数据和索引文件。
   将老的数据文件拷贝到新创建的数据文件之中。(不要只是将老文件移回新文件之中;你要保留一个副本以防某些东西出错。)
   在使用标准的修复方法。现在myisamchk -r -q应该工作了。(这不应该是一个无限循环)。
  如果你拥有表的备份文件,那么一切过程就容易的多。从备份文件中可以恢复表的描述文件,然后在检查表,,有可能还要继续使用标准的修复方法,应该纠可以解决问题了。
  非常困难的修复
  只有描述文件也破坏了,你才应该到达这个阶段。这应该从未发生过,因为在表被创建以后,描述文件就不再改变了。
  从一个备份恢复描述文件并且回到阶段2。你也可以恢复索引文件并且回到阶段1。对于后者,你应该用myisamchk -r启动。
  如果因为某种原因,数据的备份文件丢失或者没有备份文件,但是你还记得建立表的CREATE TABLE语句,那么太好了,这样还是可以恢复索引文件:
   定位到包含崩溃表的数据库目录中
   把数据文件移更安全的地方。再把数据库目录中的对应的目录删去.。
   调用mysql并发复CREATE TABLE语句建立该表。()
   退出mysql,将原始的数据文件和索引文件移回到数据库的目录中,替换刚才新建的文件。
   然后回到阶段2,修复表。也可以只移回数据文件,这样保留新的描述和索引文件,然后回到阶段1,继续用标准的方法修复表。

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