SQL Performance

APRIL 20, 2021

This is the third in a five-part series taking a deep dive into the way SQL Server row mode parallel plans start executing. A reminder of the plan ( click to enlarge ): This is the first point in the process so far that an in-flight execution plan is available (SQL Server 2016 SP1 onward) in sys.dm_exec_query_statistics_xml.

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Alex Podelko

OCTOBER 28, 2016

I am looking forward to share my thoughts on ‘Reinventing Performance Testing’ at the imPACt performance and capacity conference by CMG held on November 7-10, 2016 in La Jolla, CA. Tools, using standard languages such as C (e.g. I decided to publish a few parts here to see if anything triggers a discussion. – Cloud.

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Performance Testing Technology Technology Testing 100

SQL Performance

MAY 1, 2020

In a recent tip , I described a scenario where a SQL Server 2016 instance seemed to be struggling with checkpoint times. A SQL Server DBA myth a day: (15/30) checkpoint only writes pages from committed transactions. How It Works: When is the FlushCache message added to SQL Server Error Log? group_id = c.

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Percona

AUGUST 18, 2023

Why do you need multiple instances on the same server? You can have a host with two or three instances configured as a delayed replica of the source server with SQL Delay of, let’s say, 24hr, 12hr, and 6/3hrs. You can run multiple instances on a server to test your backups with the correct version and configs.

Programming 98

Programming Servers Database Systems 98

Scalegrid

JANUARY 19, 2024

Recovering from a MongoDB rollback involves locating rollback files, using mongorestore to load data into a separate server, cleansing unneeded data, and importing the data back into the primary cluster, coupled with ongoing monitoring and maintenance of replica sets to maintain system health.

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SQL Performance

APRIL 10, 2019

The ISO/IEC 9075:2016 standard, or SQL:2016 in short, introduces support for a profound concept called Row Pattern Recognition (RPR) in SQL. I posted a suggestion to improve SQL Server by adding support for RPR in T-SQL , but I was quite limited in the space that I had to provide the feedback. LAST ( C. NULL NULL 151.00

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SQL Performance

JULY 27, 2021

Continuing my series of articles on latches, this time I’m going to discuss the DBCC_OBJECT_METADATA latch and show how it can be a major bottleneck for consistency checks prior to SQL Server 2016 under certain circumstances. But remember, this bottleneck only happens for versions of SQL Server earlier than SQL Server 2016.

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SQL Performance

OCTOBER 14, 2020

I explained that when SQL Server optimizes a query involving derived tables, it applies transformation rules to the initial tree of logical operators produced by the parser, possibly shifting things around across what were originally table expression boundaries. Here’s the attempted solution using a CTE: WITH C AS. ( FROM Sales.

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SQL Performance

JULY 1, 2019

The results are technically non-deterministic since SQL Server could validly return any one of the rows in each group. Nevertheless, if you run this query yourself, you are quite likely to see the same result I do: The execution plan depends on the version of SQL Server used, and does not depend on database compatibility level.

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C++ Servers Database Performance 58

SQL Performance

SEPTEMBER 5, 2019

I briefly mentioned that batch mode data is normalized in my last article Batch Mode Bitmaps in SQL Server. You will need SQL Server 2016 (or later) and Developer Edition (or equivalent) to reproduce the results shown here. c = COUNT_BIG ( * ) FROM #T AS T WHERE 1 = ( SELECT 1 ) -- Avoid trivial plan.

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Performance C++ Storage Servers 81

SQL Performance

OCTOBER 29, 2019

There are multiple methods to look at poorly performing queries in SQL Server, notably Query Store, Extended Events, and dynamic management views (DMVs). CustomerID , c. Customers c JOIN Sales. CustomerTransactions ct ON c. GROUP BY c. CustomerID , c. Each option has pros and cons. CustomerID = ct.

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SQL Performance

DECEMBER 9, 2020

L0 AS ( SELECT 1 AS c. Figure 1: Plan for base CTE cardinality of 2.

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C++ Servers Testing Processing 61

SQL Server According to Bob

JANUARY 5, 2017

Last March I moved from 22 years in SQL Server support to the SQL Server development team, working on SQL Server on Linux project and reporting to Slava Oks. As Slava highlights in his recent blog post , he also contacted me in early 2015 to assist with supportability of SQL Server on Linux. There are no burning secrets.

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Servers Operating System C++ Software Engineering 40

SQL Performance

SEPTEMBER 25, 2019

For modern versions of SQL Server, this essentially means that all key columns in an index spool must be of a comparable type, no more than 900 bytes* in total, with 64 key columns or fewer. c1 UNION SELECT NULL ) AS U ) AS CA ( c ) ; Notice the Stream Aggregate below the Lazy Index Spool. Optimizer Rules.

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Performance Cache Servers Education 104

O'Reilly

FEBRUARY 4, 2025

Then, development of even higher-level compiled languages like Fortran, COBOL, and their successors C, C++, and Java meant that most programmers no longer wrote assembly code. Suddenly, the user interface was made up of human-readable documents, shown in a browser with links that could in turn call programs on remote servers.

Programming 145

Programming Google Infrastructure Internet 145

Brendan Gregg

SEPTEMBER 5, 2017

LTS (April 2016). I wrote about it in a previous post, [DTrace for Linux 2016]. Hit Ctrl-C to end. ^C C operation = 'read' usecs : count distribution 0 -> 1 : 0 | | 2 -> 3 : 0 | | 4 -> 7 : 4479 | *| 8 -> 15 : 1028 | | 16 -> 31 : 14 | | 32 -> 63 : 1 | | [.]. Oracle VM Server is based on Xen. amazon").

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Virtualization AWS Engineering Hardware 75

Rigor

JANUARY 13, 2020

These are the bestsellers in the web performance field, including the good old Speed Up Your Site (2003) by Andy King; Steve Souders’ Even Faster Web Sites (2009) ; Ilya Grigorik’s High Performance Browser Networking (2013) ; Tammy Everts’ Time is Money (2016) ; and a handful of more recent publications. Responsive and Fast.

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Performance Social Media Website Website Performance 75

SQL Server According to Bob

FEBRUARY 10, 2019

. · Failures occur from remote clients or sqlcmd executed directory on the server (/opt/mssql-tools/bin). SQL Server 2017 CU10 does not show behavior. · SQL Server 2017 CU12 exhibits the behavior. Server is a Superdome with lots of CPUs and RAM. Here is an example of a valid SQL Server login. – sqlclr.

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Smashing Magazine

JULY 6, 2021

With Luminary’s 21 years of experience in the digital space, my experience of 17 years in the CMS space as well as our focus on Headless since 2016, here are my two cents on what you should look out for. Things To Consider When Choosing A Headless CMS. Microservices architecture. Omnichannel. For content authors.

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Cache Website Mobile Google 145

Percona

JUNE 4, 2023

In this blog, we’ll provide a comparison between MariaDB vs. MySQL (including Percona Server for MySQL ). Introduction: MariaDB vs. MySQL The goal of this blog post is to evaluate, at a higher level, MariaDB vs. MySQL vs. Percona Server for MySQL side-by-side to better inform the decision making process.

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Open Source Servers Storage Scalability 52

SQL Performance

SEPTEMBER 2, 2021

SQL Server 2016 brought us STRING_SPLIT , a native function that eliminates the need for many of the custom solutions we’ve needed before. I’ve written several articles about this function (and STRING_AGG, which arrived in SQL Server 2017) since this post was written: Performance Surprises and Assumptions : STRING_SPLIT().

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Brendan Gregg

OCTOBER 7, 2018

C @ns: [256, 512) 10900 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ | [512, 1k) 18291 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@| [1k, 2k) 4998 |@@@@@@@@@@@@@@ | [2k, 4k) 57 | | [4k, 8k) 117 | | [8k, 16k) 48 | | [16k, 32k) 109 | | [32k, 64k) 3 | |. ply is also C, whereas bpftrace is C++. # Attaching 2 probes. ^C

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C++ Virtualization Programming Latency 40

Randon ASCII

FEBRUARY 25, 2018

In September of 2016 we started noticing random failures when building Chrome – 3 out of 200 builds of Chrome failed when protoc.exe, one of the executables that is part of the build, crashed with an access violation. The next step was a custom C++ program that opened the just-linked exe and called FlushFileBuffers on it.

Programming 79

Programming Hardware Cache Code 79

SQL Server According to Bob

AUGUST 23, 2016

The creation of the XTP, common access DLL requires SQL Server to generate C code, invoke the C compiler and save the DLL into the XTP directory. Bob Dorr – Principal Software Engineer SQL Server. These are additional steps that a disk based table does not perform.

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C++ Software Engineering Servers Code 40

Alex Russell

MAY 9, 2022

This blindspot usually extends up to the C-suite. Teams achieving this level of discipline about performance begin to eliminate variance from their lab data by running tests in "less noisy" environments than somewhere like a developer's laptop, a shared server, or a VM with underlying system variance.

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Performance Latency Metrics Engineering 99

Smashing Magazine

JANUARY 21, 2019

An API is the communication channel for an application to load data from the server. This relationship can be expressed through an associative array (an array of key => property) on the server-side, in which each module states its name as the key attribute and its inner modules under the property modules. Large preview ).

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Social Media Database Media Website 73

SQL Server According to Bob

DECEMBER 18, 2018

SQL Server relies on Forced-Unit-Access (Fua) I/O subsystem capabilities to provide data durability, detailed in the following documents: SQL Server 2000 I/O Basic and SQL Server I/O Basics, Chapter 2. Be sure to deploy SQL Server 2017 CU6 or newer for best data durability and performance results. “. The Back Story.

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Servers Media Cache Storage 90

Smashing Magazine

OCTOBER 26, 2018

When it comes down to how WordPress is programmed, one thing is certain: it doesn’t follow the M odel- V iew- C ontroller (MVC) design pattern that many developers are familiar with. on December 6th, 2016. If you decide to use the method described in this article, be sure you know how to fortify your server security.

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Cache Website Speed Testing 88

SQL Server According to Bob

JANUARY 28, 2018

Note: SQL Server can be a client using a linked server, allowing SQL Server to become an APP and/or an RM ). The application then uses the SQL Server client (SQL Server ODBC for this example) to establish a TDS based connection to the target SQL Server (local or remote.). Local Host Name. The olehlp!

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Servers Azure Engineering Java 40

Percona

JANUARY 14, 2019

scala','currency','println'] ? ? voting','maven'] ? ? compose','xamarin','markdown','scrum','comic'] ? ? china','sourceforge','subscription','chinese','kotlin'] ? ? systemd','gitlab','autotldr'] ? ? refugees','refugee','sanders','debates','hillary','removal','participating','removed','greece','clinton'] ? ?

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Database Analytics Blockchain Healthcare 48