Mysql – Which MySQL table to use for read-only, bulk-loaded tables

Let me start by saying, I hate ALTER. It's evil, IMHO.

Say, this is your current table schema -

CREATE TABLE my_table_of_love (
id INT UNSIGNED NOT NULL AUTO_INCREMENT,
my_value VARCHAR(40),
date_created DATE,
PRIMARY KEY(id)
) ENGINE=MyISAM CHARSET=utf8;

Here's the path I recommend -

Create a new table object that will replace the old one:

CREATE TABLE my_table_of_love_NEW (
id INT UNSIGNED NOT NULL AUTO_INCREMENT,
my_value VARCHAR(40),
date_created DATE,
PRIMARY KEY(id)
) ENGINE=InnoDB CHARSET=utf8

Insert all the rows from the old table by name into the new table:

INSERT INTO my_table_of_love_NEW (id,my_value,date_created)
SELECT id,my_value,date_created FROM my_table_of_love;

Smoke test your migration:

SELECT COUNT(*) FROM my_table_of_love_NEW;
SELECT COUNT(*) FROM my_table_of_love;
SELECT a.id,a.my_value,a.date_created FROM my_table_of_love_NEW a
LEFT JOIN my_table_of_love b ON (b.id = a.id)
WHERE a.my_value != b.my_value;

Swap table names so that you can maintain a back up in case you need to rollback.

RENAME TABLE my_table_of_love TO my_table_of_love_OLD;
RENAME TABLE my_table_of_love_NEW TO my_table_of_love;

Proceed to regression testing.

This approach becomes more and more preferable with tables with multiple indexes and millions of rows.

Thoughts?

Algorithmically, it is doing what your colleague says. But, do you see what it is doing ???

It is generating 10,000 temp tables each containing 1 row after traversing 317 million rows through in the InnoDB internal index. Each temp table is a complete regeneration of the rowids in sernumbers_results_2009 table along with executing handler_read_prev commands internally to sort the data by an index scan from the back of the internal rowid index. Also, please remember you are dealing with InnoDB. Who knows what Multiversioning (via MVCC) is going on so that the INSERT is completed without interference and with rollback capabilities.

Is there any reason why this query wouldn't work for you ???

INSERT INTO sernumbers_results_2009
SELECT * FROM sernumbers_results
ORDER BY rowid DESC LIMIT 10000;

This will definitely generate one temp table.

Give it a Try !!!