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Search Results for: io wait

Do not trust vmstat IOwait numbers

I’ve been running a benchmark today on my old test box with conventional hard drives (no raid with BBU) and noticed something unusual in the CPU utilization statistics being reported. The benchmark was run like …

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1 Billion Insertions – The Wait is Over!

iiBench measures the rate at which a database can insert new rows while maintaining several secondary indexes. We ran this for 1 billion rows with TokuDB and InnoDB starting last week, right after we launched …

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Featured Talk: The Future of Replication is Today: New Features in Practice

In the past years, both MySQL 5.6, MySQL 5.7 and MariaDB 10 have been successful implementing new features. For many DBAs, the “old way” of replicating data is comfortable so taking the action to implement …

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The language of compression

Storage. Everyone needs it. Whether your data is in MySQL, a NoSQL, or somewhere in the cloud, with ever-growing data volumes – along with the need for SSDs to cut latency and replication to provide …

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Multi-source replication in MySQL 5.7 vs Tungsten Replicator

MySQL 5.7 comes with a new set of features and multi-source replication is one of them. In few words this means that one slave can replicate from different masters simultaneously. During the last couple of …

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Update on the InnoDB double-write buffer and EXT4 transactions

In a post, written a few months ago, I found that using EXT4 transactions with the “data=journal” mount option, improves the write performance significantly, by 55%, without putting data at risk. Many people commented on …

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MongoDB’s flexible schema: How to fix write amplification

Being schemaless is one of the key features of MongoDB. On the bright side this allows developers to easily modify the schema of their collections without waiting for the database to be ready to accept …

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Staying ahead of MySQL operational problems at Percona Live

I’ve started my long journey from Florianópolis, Brazil, to Santa Clara, California and I type this words while waiting for a connection flight. Next Wednesday, Daniel Guzmán Burgos and I will be presenting in the …

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InnoDB locks and deadlocks with or without index for different isolation level

Recently, I was working on one of the issue related to locks and deadlocks with InnoDB tables and I found very interesting details about how InnoDB locks and deadlocks works with or without index for different Isolation levels. …

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