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Search Results for: using explain index

Lock Diagnostics and Index Usage Statistics in TokuMX v1.2.1

TokuMX v1.2.1 introduces two simple new features to help you understand the performance characteristics of your database: lock diagnostics and index usage statistics. We’d like to take you through a few examples of what these …

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Why Unique Indexes are Bad

Before creating a unique index in TokuMX or TokuDB, ask yourself, “does my application really depend on the database enforcing uniqueness of this key?” If the answer is ANYTHING other than yes, do not declare …

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MySQL 5.6.10 Optimizer Limitations: Index Condition Pushdown

While preparing the webinar I will deliver this Friday, I ran into a quite interesting (although not very impacting) optimizer issue: a “SELECT *” taking half the time to execute than the same “SELECT one_indexed_column” …

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MongoDB + Fractal Tree Indexes = High Compression

One doesn’t have to look far to see that there is strong interest in MongoDB compression. MongoDB has an open ticket from 2009 titled “Option to Store Data Compressed” with Fix Version/s planned but not …

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The Optimization That (Often) Isn’t: Index Merge Intersection

Prior to version 5.0, MySQL could only use one index per table in a given query without any exceptions; folks that didn’t understand this limitation would often have tables with lots of single-column indexes on …

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Full table scan vs full index scan performance

Earlier this week, Cédric blogged about how easy we can get confused between a covering index and a full index scan in the EXPLAIN output. While a covering index (seen with EXPLAIN as Extra: Using …

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Tools and Techniques for Index Design Webinar Questions Followup

I presented a webinar this week to give an overview of Tools and Techniques for Index Design. Even if you missed the webinar, you can register for it, and you’ll be emailed a link to …

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Three Ways that Fractal Tree Indexes Improve SSD for MySQL

Since Fractal Tree indexes turn random writes into sequential writes, it’s easy to see why they offer a big advantage for maintaining indexes on rotating disks. It turns out that that Fractal Tree indexing also …

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Strange Loop Talk on Indexing

At next week’s Strange Loop conference, I will give a talk on “Understanding Indexing”. The session is 10 am Monday, September 24th, and will be held in the Midland States Room.

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Webinar: Understanding Indexing

Three rules on making indexes around queries to provide good performance Application performance often depends on how fast a query can respond and query performance almost always depends on good indexing. So one of the …

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