(mysql.info.gz) Open tables

Info Catalog

(mysql.info.gz) MyISAM key cache

(mysql.info.gz) Optimizing Database Structure

(mysql.info.gz) Table cache

 
 7.4.7 How MySQL Counts Open Tables
 ----------------------------------
 
 When you execute a `mysqladmin status' command, you'll see something
 like this:
 
      Uptime: 426 Running threads: 1 Questions: 11082
      Reloads: 1 Open tables: 12
 
 The `Open tables' value of 12 can be somewhat puzzling if you have only
 six tables.
 
 MySQL is multi-threaded, so there may be many clients issuing queries
 for a given table simultaneously. To minimize the problem with multiple
 client threads having different states on the same table, the table is
 opened independently by each concurrent thread. This takes some memory
 but normally increases performance.  With `MyISAM' tables, one extra
 file descriptor is required for the data file for each client that has
 the table open. (By contrast, the index file descriptor is shared
 between all threads.) The `ISAM' storage engine shares this behavior.
 
 You can read more about this topic in the next section.  Table
 cache.
 

Info Catalog

(mysql.info.gz) MyISAM key cache

(mysql.info.gz) Optimizing Database Structure

(mysql.info.gz) Table cache