Brendan Gregg

SEPTEMBER 25, 2021

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

Speed Java AWS Virtualization 126

Percona

JANUARY 14, 2019

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

Database 40

Database Analytics Blockchain Healthcare 40

SQL Performance

OCTOBER 29, 2019

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. CustomerID , c. Customers c JOIN Sales. CustomerTransactions ct ON c. GROUP BY c. CustomerID , c. CustomerID = ct.

C++ 74

C++ Database Servers Tuning 74

Brendan Gregg

SEPTEMBER 25, 2021

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

Speed Java AWS Virtualization 40