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Search Results for: unique key

Fractal Tree library as a Key-Value store

As you may know, Tokutek is now part of Percona and I would like to explain some internals of TokuDB and TokuMX – what performance benefits they bring, along with further optimizations we are working …

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Illustrating Primary Key models in InnoDB and their impact on disk usage

On a recent engagement I worked with a customer who makes extensive use of UUID() values for their Primary Key and stores it as char(36), and their row count on this example table has grown to …

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7 Key MySQL clustering technologies – A joint webinar with 451 Research

I’m looking forward to Wednesday’s joint webinar on MySQL clustering technologies with Matt Aslett, research director of data management and analytics over at 451 Research. We’ll be participating in a live, in-depth discussion of MySQL …

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What’s new in TokuMX 1.4, Part 1: Primary keys

We just released version 1.4.0 of TokuMX, our high-performance distribution of MongoDB. There are a lot of improvements in this version (release notes), the most of any release yet. In this series of blog posts, …

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InnoDB scalability issues due to tables without primary keys

Each day there is probably work done to improve performance of the InnoDB storage engine and remove bottlenecks and scalability issues. Hence there was another one I wanted to highlight: Scalability issues due to tables …

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How InnoDB promotes UNIQUE constraints

The other day I was running pt-duplicate-key-checker on behalf of a customer and noticed some peculiar recommendations on an InnoDB table with an odd structure (no PRIMARY key, but multiple UNIQUE constraints). This got me …

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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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Why “insert … on duplicate key update” May Be Slow, by Incurring Disk Seeks

In my post on June 18th, I explained why the semantics of normal ad-hoc insertions with a primary key are expensive because they require disk seeks on large data sets. I previously explained why it …

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Better Primary Keys, a Benefit to TokuDB’s Auto Increment Semantics

In our last post, Bradley described how auto increment works in TokuDB. In this post, I explain one of our implementation’s big benefits, the ability to combine better primary keys with clustered primary keys. In …

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Checking table definition consistency with mysqldiff

Data inconsistencies in replication environments are a pretty common. There are lots of posts that explain how to fix those using pt-table-checksum and pt-table-sync. Usually we only care about the data but from time to …

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