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Search Results for: insert ... select

INSERT INTO … SELECT Performance with Innodb tables.

Everyone using Innodb tables probably got use to the fact Innodb tables perform non locking reads, meaning unless you use some modifiers such as LOCK IN SHARE MODE or FOR UPDATE, SELECT statements will not …

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Multi-Valued INSERTs, AUTO_INCREMENT & Percona XtraDB Cluster

A common migration path from standalone MySQL/Percona Server to a Percona XtraDB Cluster (PXC) environment involves some measure of time where one node in the new cluster has been configured as a slave of the …

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Edge-case behavior of INSERT…ODKU

A few weeks back, I was working on a customer issue wherein they were observing database performance that dropped through the floor (to the point of an outage) roughly every 4 weeks or so. Nothing …

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Avoiding auto-increment holes on InnoDB with INSERT IGNORE

Are you using InnoDB tables on MySQL version 5.1.22 or newer? If so, you probably have gaps in your auto-increment columns. A simple INSERT IGNORE query creates gaps for every ignored insert, but this is …

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High Rate insertion with MySQL and Innodb

I again work with the system which needs high insertion rate for data which generally fits in memory. Last time I worked with similar system it used MyISAM and the system was built using multiple …

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Concurrent inserts on MyISAM and the binary log

Recently I had an interesting surprise with concurrent inserts into a MyISAM table. The inserts were not happening concurrently with SELECT statements; they were blocking and the process list was filling up with queries in …

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Generating test data from the mysql> prompt

There are a lot of tools that generate test data.  Many of them have complex XML scripts or GUI interfaces that let you identify characteristics about the data. For testing query performance and many other …

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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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pt-online-schema-change and binlog_format

Statement-based or row-based, or mixed?  We’ve all seen this discussed at length so I’m not trying to rehash tired arguments.  At a high level, the difference is simple: Statement based replication (SBR) replicates the SQL …

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Replication of MEMORY (HEAP) 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 …

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