从另一个MyISAM表自动加载MEMORY表

Question

To increase server performance, I decided to use memory table for faster reading user's info.

My question is: How to auto load MEMORY table from another MyISAM table after server shutdown?

I can check rows count every time I want to lookup in MEMORY and then, load row by row by a PHP script, but it takes time to read 2,000,000 records from MyISAM and save in MEMORY. and checking rows count. although it is not thread safe and I should take care of it.

Is there any better way?

Answer 1

It appears you can also configure MySQL to automatically run certain statements on startup using the init_file option:

http://dev.mysql.com/doc/refman/5.6/en/server-options.html#option_mysqld_init-file

You could tell it to run a file that populates your memory table.

Another consideration, if you need to occasionally update your memory table is to use events:

http://dev.mysql.com/doc/refman/5.6/en/create-event.html

Answer 2

Simplest would be to modify whatever script is starting MySQL (mysqld_safe?) and have it run 'mysql' to issue a command to run a stored proc which does your table populating. I don't believe MySQL has anything internally that you can trigger automatically at startup, or any kind of internal job scheduler.

Answer 3

I have solved this problem in the following way. 1. Create a script on php which is set to cron. Draft version:

$connection = new PDO(....)
$sql = "Select id from table_memory limit 1";
$result = $connection->query($sql)->fetchColumn();
if (!$result) {
    $sql = "select * into outfile '/path' from main_table";
    $connection->exec($sql);
    if (file_exists('/path')) {
       $sql = "LOAD DATA INFILE '/path' INTO table_memory";
       $connection->exec($sql);
    }
}

//final checking if necessary and send mail or other notification

References: http://dev.mysql.com/doc/refman/5.0/en/load-data.html