SQL Performance

AUGUST 23, 2019

In traditional row-mode execution plans, SQL Server may introduce a Bitmap operator as part of performing early semi join reduction before a parallel hash or merge join. There have been major improvements since the first appearance of the batch mode execution engine in SQL Server 2012. Background. The Query Optimizer. Bitmap Choice.

Servers 75

Servers Engineering Efficiency Retail 75

Brendan Gregg

JULY 4, 2021

AWS Graviton2); for memory with the arrival of DDR5 and High Bandwidth Memory (HBM) on-processor; for storage including new uses for 3D Xpoint as a 3D NAND accelerator; for networking with the rise of QUIC and eXpress Data Path (XDP); and so on.

Performance 52

Performance Latency Hardware Storage 52

Brendan Gregg

NOVEMBER 29, 2017

In this configuration, the AMI and boot is paravirt (PV), the kernel is making hypercalls instead of privileged instructions, and the system is using paravirt network and storage drivers. It's all a bit confusing, and I wrote about this in 2014: [Xen Modes]. This was extended to instance storage devices for the x1.32xlarge in 2016.

Virtualization 111

Virtualization AWS Hardware Storage 111

Brendan Gregg

FEBRUARY 28, 2023

My personal opinion is that I don't see a widespread need for more capacity given horizontal scaling and servers that can already exceed 1 Tbyte of DRAM; bandwidth is also helpful, but I'd be concerned about the increased latency for adding a hop to more memory.

Performance 52

Performance Latency Cache Virtualization 52

SQL Performance

APRIL 8, 2019

Back on December 5, 2017, Microsoft announced that they were using AMD EPYC 7551 processors in their storage-optimized Lv2-Series virtual machines. These AMD EPYC processors have a number of advantages for SQL Server workloads, as I will explain in this article. Since then, Microsoft has changed the naming of this series to Lsv2.

Azure 42

Azure Virtualization Storage Benchmarking 42

High Scalability

JUNE 22, 2018

Charlie Demerjian : what does Intel have planned for their server roadmap? For the same reason the 14/10nm messaging is causing consternation among investors, but the server side is in much worse shape. using them to respond to storage events on s3 or database events or auth events is super easy and powerful. How bad is it?

Internet 113

Internet Internet Scalability Artificial Intelligence 113

SQL Performance

MARCH 17, 2020

Back in 2014, I wrote an article called Performance Tuning the Whole Query Plan. This follow-up post revisits the question for SQL Server 2019, using a larger number of rows. It has 32GB RAM, with 24GB available to the SQL Server 2019 instance. Test Environment. The cost threshold for parallelism is set to 50.

Servers 86

Servers Tuning Database Efficiency 86

SQL Performance

MAY 16, 2019

Without this guarantee, SQL Server might add index rows that are not sorted correctly, which would not be good. For INSERT.SELECT , SQL Server makes its own determination whether to ensure rows are presented to the Clustered Index Insert operator in key order or not. DMLRequestSort Conditions.

Cache 67

Cache Servers Testing Storage 67

SQL Performance

MAY 1, 2019

The summary rows for heap tables without indexes are the same in both documents (no changes for SQL Server 2016): An explicit TABLOCK hint is not the only way to meet the requirement for table-level locking. The inputs to this calculation are: The version of SQL Server. The estimated number of rows leading into the Insert operator.

Servers 47

Servers Database Testing Performance 47

SQL Server According to Bob

JUNE 3, 2016

SQL Server 2016 changes the internal design to (CheckScanner), applying no lock semantics and a design similar to those used with In-Memory Optimized (Hekaton) objects, allowing DBCC operations to scale far better than previous releases. Ryan Stonecipher – Principle SQL Server Software Engineer. SQL Server. set nocount on.

Hardware 40

Hardware Cache Servers Software Engineering 40

Abhishek Tiwari

NOVEMBER 3, 2018

If you put your whole website on CDN, technically you don’t need a large number of server infrastructure and CMS licenses. They often get blindsided by vendor’s pitch and end-up making decision based on some fancy demos (see my post from 2014 on Adobe AEM ). Circa 2014, I was working with a big Japanese automotive brand in Australia.

Systems 63

Systems Cache Website Network 63

Brendan Gregg

NOVEMBER 28, 2017

In this configuration, the AMI and boot is paravirt (PV), the kernel is making hypercalls instead of privileged instructions, and the system is using paravirt network and storage drivers. It's all a bit confusing, and I wrote about this in 2014: [Xen Modes]. This was extended to instance storage devices for the x1.32xlarge in 2016.

Virtualization 40

Virtualization AWS Hardware Storage 40

SQL Performance

APRIL 23, 2019

In SQL Server 2012, grouped (vector) aggregation was able to use parallel batch-mode execution, but only for the partial (per-thread) aggregate. SQL Server 2014 added the ability to perform parallel batch-mode grouped aggregation within a single Hash Match Aggregate operator. Columnstore storage. Introduction.

Servers 67

Servers Testing Metrics Storage 67

SQL Performance

MAY 29, 2019

It can be activated from SQL Server 2008 to 2014 inclusive using documented trace flag 610. From SQL Server 2016 onward, FastLoadContext is enabled by default ; the trace flag is not required. For more background, see the Data Performance Loading Guide and the Tiger Team notes on the behaviour changes for SQL Server 2016.

Cache 64

Cache Testing Servers Code 64

Alex Russell

MARCH 6, 2021

A then-representative $200USD device had 4-8 slow (in-order, low-cache) cores, ~2GiB of RAM, and relatively slow MLC NAND flash storage. mid-priced Androids were slightly faster than 2014's iPhone 6. The Moto G4 , for example. The cheapest (high volume) Androids perform like 2012/2013 iPhones, respectively.

Performance 124

Performance Network Cache Metrics 124

Percona

JANUARY 14, 2019

In a partitioned massively parallel database system, the storage format and sorting algorithm may not be optimized for that operation as we are reading multiple partitions in parallel. codecs','imgur','floppy','codec','adobe','android'] ? ? scala','currency','println'] ? ? voting','maven'] ? ? systemd','gitlab','autotldr'] ? ?

Database 40

Database Analytics Blockchain Healthcare 40

Brendan Gregg

SEPTEMBER 5, 2017

Oracle VM Server is based on Xen. I came up with a great demo where I could break Solaris 9 and 10 servers in the same way, then demonstrate how it would take an hour and a reboot cycle to fix Solaris 9, but minutes and no reboot to fix Solaris 10. amazon"). I also wrote and published an entertaining SMF manifest that played music.

Virtualization 76

Virtualization AWS Engineering Hardware 76

SQL Server According to Bob

DECEMBER 31, 2018

How It Works: XEvent Output and Visualization SQL Server Management Studio Provides–“XE Profiler” Use the SSMS XEvent Profiler. Using SQL Server Management Studio (SSMS) and storing the events in a table requires reading the events, streaming to table storage followed by an order by event sequence query. TSQL Sample Session.

Efficiency 40

Efficiency Code Servers Cache 40

Sutter's Mill

MARCH 11, 2024

Kubernetes Secrets on public GitHub repos), misconfigured servers (e.g., Do configure your servers correctly, especially public Internet-facing ones. That’s pretty easy to statically guarantee, except for some cases of the unused parts of lazily constructed array/vector storage. Don’t store secrets in code. (Or,

C++ 139

C++ Programming Code Java 139

O'Reilly

JULY 25, 2023

To provide some coherence to the music, I decided to use Taylor Swift songs since her discography covers the time span of most papers that I typically read: Her main albums were released in 2006, 2008, 2010, 2012, 2014, 2017, 2019, 2020, and 2022. This choice also inspired me to call my project Swift Papers.

Programming 98

Programming Code Design Benchmarking 98