How to preload tables into INNODB buffer pool with

问题:

I have an e-commerce application that uses MySQL, and I'd like it to be faster. When a part # is accessed on the website that has been accessed before, the part loads quickly because all the necessary data is already in the INNODB buffer pool. However, if the part # has never been loaded before, that data isn't in the buffer pool yet, so it needs to be read from disk, and that is slow. I set my INNODB buffer pool to be 2GB, and this entire database is only about 350MB, so there is plenty of room to load the entire database in the buffer pool. I can see from the INNODB statistics that only about half the buffer pool is used right now.

I've found references to pre-loading the data, also known as "warming up" the buffer pool, such as Quickly preloading Innodb tables in the buffer pool or mysqldump.azundris.com/archives/70-Innodb-cache-preloading-using-blackhole.html. The strategy basically involves forcing a table scan on each table since MySQL doesn't have a native way for preloading the data.

I don't want to manually create a script that lists every single table in my database and have to do this. How can I create a script that goes through and does a select for each table automatically, and automatically picks out a non-indexed column so that a table scan is performed?

回答1:

This should give you a list of queries to run ;)

SELECT 
  CONCAT('SELECT ',MIN(c.COLUMN_NAME),' FROM ',c.TABLE_NAME,' WHERE ',MIN(c.COLUMN_NAME),' IS NOT NULL')
FROM
  information_schema.COLUMNS AS c
LEFT JOIN (
  SELECT DISTINCT
    TABLE_SCHEMA,TABLE_NAME,COLUMN_NAME
  FROM
    information_schema.KEY_COLUMN_USAGE
) AS k
USING
  (TABLE_SCHEMA,TABLE_NAME,COLUMN_NAME)
WHERE
  c.TABLE_SCHEMA = 'yourDatabase'
  AND k.COLUMN_NAME IS NULL
GROUP BY
  c.TABLE_NAME

You can put it into stored procedure, and go over the resultset with cursor. Create a prepared statement from each row, and execute.

回答2:

This query will return table names in your database, so you don't have to input them manually:

SELECT TABLE_NAME FROM information_schema.TABLES WHERE TABLE_SCHEMA = 'database name'

Then for each table name force table scan.