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I didn’t have time to answer all of the questions during Wednesday’s MySQL webinar, “5 Percona Toolkit Tools That Could Save Your Day,” but as promised, here are all of the questions and my answers. (A recording is available here.)
Q: One of the links to download the Percona Toolkit for MySQL (percona.com/get/percona-toolkit.tgz) doesn’t work!
A: You’re
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On April 3 at 10 a.m. PST, I’ll be giving a webinar titled “5 Percona Toolkit Tools for MySQL That Could Save Your Day.” In this presentation you’ll learn how to perform typical but challenging MySQL database administration tasks.
My focus will be on the following tools:
Stéphane Combaudon of Dailymotion.
Index: separate data structure to speed up SELECTs. Think of index in a book. In MySQL, key=index. Consider that indexes are trees.
InnoDB’s clustered index – data is stored with the Primary Key (PK) so PK lookups are fast. Secondary keys hold the PK values. Designing InnoDB PK’s with care is critical for performance.
An index can filter and/or sort values. An index can contain all the fields needed for the query you don’t need to go to the table (a covering index).
MySQL only uses 1 index per table per query (not 100% true – OR clauses), so think of a composite index when you can. Can’t index TEXT fields (use a prefix). Same for BLOBs and long VARCHARs.
Indexes: speed up queries, increases the size of your dataset, slows down writes. How
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