mysql drop table都作了什么

 

当用户发出 DROP TABLE 命令后：
############# MYSQL SERVER 处理删除一个表 ##################
/* Sql_table.cc  delete (drop) tables. */
bool mysql_rm_table( )
  /*   Execute the drop of a normal or temporary table */
  int mysql_rm_table_part2 ()

   /* Remove matching tables from the HANDLER’s hash table.  */
   void mysql_ha_rm_tables ()
    /* Mark all entries with the table as deleted to force an reopen of the table */
    remove_table_from_cache ()

   /* remove engine files */  LINE 2024
       int handler::ha_delete_table(const char *name)
          file->ha_delete_table(path)   line 1991
             int handler::delete_table(const char *name) //删除物理表文件；
                 /* 这里INNODB继承了父类handler ，
                 实际调用的是这个 int ha_innobase::delete_table
                 转到下面：   #### INNODB 处理删除一个表 ####
                 若是是其余引擎，则直接删除数据文件，往下走*/
                int mysys::my_delete_with_symlink(const char *name, myf MyFlags)
                  int mysys::my_delete(const char *name, myf MyFlags)

   /* Delete the table definition file */  LINE 2042
    int mysys::my_delete()
  /* clear query cache*/
      query_cache_invalidate3
    /* writes to BINLOG */
############# INNODB 处理删除一个表 ##################
/* Drops a table from an InnoDB database.  */
int ha_innobase::delete_table( const char* name) ; // 从INNODB删除表
   int row_drop_table_for_mysql()
     /* 外键关联检查 */
     /* 锁住数据字典（独占锁）*/
        /* Serialize data dictionary operations with dictionary mutex:
        row_mysql_lock_data_dictionary(trx);

     /* 更新数字字典(MEMDB,information_schema), line 3178 */
        que_eval_sql(info, “PROCEDURE DROP_TABLE_PROC () IS\n”
        /*这里是经过一个PROCEDURE来处理的*/

     /* 更新数字字典(CACHE) */
        void dict_table_remove_from_cache(dict_table_t* table))

     /* 删除数据文件
          /* Deletes a single-table tablespace */
          ibool fil_delete_tablespace()

            /* Frees a space object from the tablespace memory cache*/
            ibool fil_space_free ()

            /* Deletes a file. The file has to be closed before calling this. */
            ibool os_file_delete ()
              unlink((const char*)name);

     /* 释放锁 */
        row_mysql_unlock_data_dictionary(trx);