(mysql.info) myisam-table-close

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(mysql.info) corrupted-myisam-tables

(mysql.info) myisam-table-problems

 
 14.1.4.2 Problems from Tables Not Being Closed Properly
 .......................................................
 
 Each `MyISAM' index file (`.MYI' file) has a counter in the header that
 can be used to check whether a table has been closed properly. If you
 get the following warning from `CHECK TABLE' or `myisamchk', it means
 that this counter has gone out of sync:
 
      clients are using or haven't closed the table properly
 
 This warning doesn't necessarily mean that the table is corrupted, but
 you should at least check the table.
 
 The counter works as follows:
 
    * The first time a table is updated in MySQL, a counter in the
      header of the index files is incremented.
 
    * The counter is not changed during further updates.
 
    * When the last instance of a table is closed (because a `FLUSH
      TABLES' operation was performed or because there is no room in the
      table cache), the counter is decremented if the table has been
      updated at any point.
 
    * When you repair the table or check the table and it is found to be
      okay, the counter is reset to zero.
 
    * To avoid problems with interaction with other processes that might
      check the table, the counter is not decremented on close if it was
      zero.
 
 In other words, the counter can become incorrect only under these
 conditions:
 
    * A `MyISAM' table is copied without first issuing `LOCK TABLES' and
      `FLUSH TABLES'.
 
    * MySQL has crashed between an update and the final close.  (Note
      that the table may still be okay, because MySQL always issues
      writes for everything between each statement.)
 
    * A table was modified by `myisamchk --recover' or `myisamchk
      --update-state' at the same time that it was in use by `mysqld'.
 
    * Multiple `mysqld' servers are using the table and one server
      performed a `REPAIR TABLE' or `CHECK TABLE' on the table while it
      was in use by another server. In this setup, it is safe to use
      `CHECK TABLE', although you might get the warning from other
      servers.  However, `REPAIR TABLE' should be avoided because when
      one server replaces the data file with a new one, this is not
      known to the other servers.
 
      In general, it is a bad idea to share a data directory among
      multiple servers. See  multiple-servers, for additional
      discussion.
 

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(mysql.info) corrupted-myisam-tables

(mysql.info) myisam-table-problems