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The Speed of Time

Brendan Gregg

These strange questions came to the fore back in 2014 when Netflix was switching services from CentOS Linux to Ubuntu, and I helped debug several weird performance issues including one I'll describe here. A Cassandra database cluster had switched to Ubuntu and noticed write latency increased by over 30%. How would you _time_ time?

Speed 126
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Upcoming Webinar Tuesday, 7/31: Using MySQL for Distributed Database Architectures

Percona

Please join Percona’s CEO, Peter Zaitsev as he presents Using MySQL for Distributed Database Architectures on Tuesday, July 31st, 2018 at 7:00 AM PDT (UTC-7) / 10:00 AM EDT (UTC-4). 5000 named Percona to their list in 2013, 2014, 2015 and 2016. Register Now.

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Should You Use ClickHouse as a Main Operational Database?

Percona

What if we use ClickHouse (which is a columnar analytical database) as our main datastore? Well, typically, an analytical database is not a replacement for a transactional or key/value datastore. Although such databases can be very efficient with counts and averages, some queries will be slow or simply non existent. Processed 4.15

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Finding Distinct Values Quickly

SQL Performance

Back in 2014, I wrote an article called Performance Tuning the Whole Query Plan. I will be using the 50GB Stack Overflow 2013 database , but any large table with a low number of distinct values would do. The Stack Overflow 2013 database comes without nonclustered indexes to minimize download time. Test Environment.

Servers 86
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Common SQL Server Mishaps

SQL Performance

This article will expand on my previous article and point out how these apply to SQL Server , Azure SQL Database , and Azure SQL Managed Instance. When looking at backups, I check for recovery model and the current history of backups for each database. Azure SQL Database and Azure Managed Instance have managed backups.

Servers 49
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The Speed of Time

Brendan Gregg

These strange questions came to the fore back in 2014 when Netflix was switching services from CentOS Linux to Ubuntu, and I helped debug several weird performance issues including one I'll describe here. A Cassandra database cluster had switched to Ubuntu and noticed write latency increased by over 30%. How would you _time_ time?

Speed 40
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Analyzing "death by a thousand cuts" workloads

SQL Performance

In order to use Query Store and Extended Events, you have to configure them in advance – either enabling Query Store for your database(s), or setting up an XE session and starting it. [ dbid ] ) AS [ Database Name ] , REPLACE ( REPLACE ( LEFT ( t. [ SELECT TOP ( 50 ) DB_NAME ( t. [

C++ 74