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Search Results for: covering indexes

Covering Indexes: How many indexes do you need?

I’ve recently been blogging about how partitioning is a poor man’s answer to covering indexes. I got the following comment from Jaimie Sirovich: “There are many environments where you could end up creating N! indices …


Clustering indexes vs. Covering indexes

Yesterday, I (Zardosht) posted an entry introducing clustering indexes. Here, I elaborate on three differences between a clustering index and a covering index: Clustering indexes can create indexes that would otherwise bounce up against the …


Covering Indexes: Orders-of-Magnitude Improvements

The talk I gave at the Percona Performance Conference at the MySQL Users Conference in April 2009 can be found here. This talk provides some examples where covering indexes help, and then describes a performance …


Covering index and prefix indexes

I already wrote in the blog as well mentioned in presentation there is often a choice you have to make between having prefix index – which can be significantly smaller in size and having index …


Introducing TokuMX Clustering Indexes for MongoDB

Since introducing TokuMX, we’ve discussed benefits that TokuMX has for existing MongoDB applications that require no changes. In this post, I introduce an extension we’ve made to the indexing API: clustering indexes, a tool that …


Quickly finding unused indexes (and estimating their size)

I had a customer recently who needed to reduce their database size on disk quickly without a lot of messy schema redesign and application recoding.  They didn’t want to drop any actual data, and their …


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 …


Explaining Indexes with a Library Metaphor

My favorite metaphor for explaining indexes is comparing them to index cards in an old library. In an old library, you used to (or still do) have index cards at the front desk which have …


Multi Column indexes vs Index Merge

The mistake I commonly see among MySQL users is how indexes are created. Quite commonly people just index individual columns as they are referenced in where clause thinking this is the optimal indexing strategy. For …


3 ways MySQL uses indexes

I often see people confuse different ways MySQL can use indexing, getting wrong ideas on what query performance they should expect. There are 3 main ways how MySQL can use the indexes for query execution, …