Before I start a story about the data recovery case I worked on yesterday, here’s a quick tip – having a database backup does not mean you can restore from it. Always verify your backup can be used to restore the database! If not automatically, do this manually, at least once a month. No, seriously […]
Search Results for: too many tables
Some Applications need to store some transient data which is frequently regenerated and MEMORY table look like a very good match for this sort of tasks. Unfortunately this will bite when you will be looking to add Replication to your environment as MEMORY tables do not play well with replication.
This page contains links to various tools we found helpful to use in practice. Some tools are written by us, others by third parties, yet another ones may be shipped with your operating system you just need to find they are there. Percona Toolkit Percona Toolkit is a great set of tools for MySQL Performance […]
I’ve just been pointed to the nice tool which I was waiting for years to see. It is fincore – little perl script which allows you to see what pages of file are cached in OS memory. This is really cool.
Many Open Source software solutions use database per user (or set of tables per user) which starts to cause problems if it is used on massive scale (blog hosting, forum hosting etc), resulting of hundreds of thousands if not millions of tables per server which can become really inefficient. It is especially inefficient with Innodb […]
As you might know while running GROUP BY and some other kinds of queries MySQL needs to create temporary tables, which can be created in memory, using MEMORY storage engine or can be created on disk as MYISAM tables. Which one will be used depends on the allowed tmp_table_size and also by the data which […]
We’re working with web site preparing for massive growth. To make sure it handles large data sets as part of the process we work on generation test database of significant size as testing your application on table with 1000 rows may well give you very dangerous false sense of security. One of the process web […]
I was restarting MySQL on box with 50.000 of Innodb tables and again it took couple of hours to reach decent performance because of “Opening Tables” stage was taking long. Part of the problem is Innodb is updating stats on each table open which is possibly expensive operation, but really it is only great test […]
Starting MySQL 4.1, MySQL had support for what is called derived tables, inline views or basically subselects in the from clause. In MySQL 5.0 support for views was added. These features are quite related to each other but how do they compare in terms of performance ?
If you’ve been reading enough database related forums, mailing lists or blogs you probably heard complains about MySQL being unable to handle more than 1.000.000 (or select any other number) rows by some of the users. On other hand it is well known with customers like Google, Yahoo, LiveJournal,Technocarati MySQL has installations with many billions […]