SQL Performance

NOVEMBER 1, 2019

As I embark on my first PASS Summit in a few years, it is hard to contain my excitement about the newest version of SQL Server. As you may recall, back in SQL Server 2016 SP1, they opened up all of the programming surface features to all editions, and many (but certainly not all) of the performance and availability features.

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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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C++ Servers Database Code 54

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. Still, if you stack a bunch of high-transaction databases on there, checkpoint processing can get pretty sluggish. A SQL Server DBA myth a day: (15/30) checkpoint only writes pages from committed transactions.

C++ 58

C++ Database Servers Storage 58

Percona

SEPTEMBER 19, 2023

This type of backup is suitable for large, important databases that need to be recovered quickly when problems occur. Physical backups are the backups that consist of raw copies of the directories and files that store database contents. Copyright (c) 2016, 2023, Oracle and/or its affiliates. Type 'help' or '?'

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C++ Servers Storage Speed 104

Percona

APRIL 12, 2023

Whereas many open source software offerings — like the community version of MySQL — use the GNU General Public License ( GPL ), MongoDB has been under the GNU Affero General Public License ( AGPL ) and more recently under the Server Side Public License ( SSPL ), introduced by MongoDB itself. Is MongoDB free to use?

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Open Source Programming Database Servers 80

SQL Server According to Bob

JULY 13, 2016

20+ years ago when I joined Microsoft I was handed a diskette (maybe it was two), and was told “Here is SQL Server. So I proceeded to install SQL Server 4.20 There was a GUI as part of setup but within just a few clicks, SQL Server was installed and ready for use. So now there are more choices to make when installing SQL Server.

Servers 40

Servers Media Engineering Virtualization 40

SQL Server According to Bob

NOVEMBER 8, 2016

SQL Server 2016 Service Pack 1 (all SKUs) , in combination with Windows Server 2016 (All SKUs) or Windows 10 Client introduces non-volatile memory support for the tail of the log file (LDF) which can significantly increase transaction throughput. Create / Alter Database … LOG ON. NVDIMM is measured in nanoseconds.

Cache 40

Cache Servers Media Storage 40

SQL Server According to Bob

JANUARY 26, 2017

My goal is to resolve mysteries about SQL Server I encounter but do this without going straight the source code first. The first case that helped me start this journey was asked by a MVP within the SQL Server community (his first name starts with Joey<g>). That is to ensure your database is encrypted at the file level.

Servers 40

Servers Database Azure Cache 40

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. What is MariaDB?

Open Source 52

Open Source Servers Storage Scalability 52

SQL Server According to Bob

APRIL 25, 2017

I recently visited a customer onsite and presented to them topics on SQL Server 2016. One question I got went like this “I’ve tried to restore a database on SQL Server using the WITH STATS option. We now have a new way of instrumenting the backup/restore process for any database or transaction log.

Servers 40

Servers Database Processing Virtualization 40

SQL Server According to Bob

APRIL 21, 2017

I recently visited a customer onsite and presented to them topics on SQL Server 2016. One question I got went like this “I’ve tried to restore a database on SQL Server using the WITH STATS option. We now have a new way of instrumenting the backup/restore process for any database or transaction log.

Servers 40

Servers Database Processing Virtualization 40

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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Servers Network Database Systems 40

SQL Server According to Bob

JULY 12, 2016

Trace flags 2562 and 2549 are documented in knowledgebase article: [link] and the blog post [link] highlights the SQL 2016 DBCC performance improvements. For SQL Server 2008, 2012 and 2014 the trace flag behavior remains the same. For SQL Server 2016 the trace flags are available but the behavior may be altered by the design changes.

Servers 40

Servers Design Engineering Database 40

SQL Performance

DECEMBER 9, 2020

You can create supporting tables in the user database if needed. I tested my solutions in SQL Server 2019 Enterprise edition. SQL Server chose row mode processing for all previously shown solutions by default. There are a couple of ways to get SQL Server to use batch processing here. You can add hints as needed.

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C++ Servers Testing Processing 114

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.

C++ 58

C++ Servers Database Performance 58

SQL Performance

AUGUST 14, 2019

In my examples I'll use a sample database called TSQLV5. You can find the script that creates and populates this database here , and its ER diagram here. SQL Server 2019 introduces batch mode on rowstore support, so you can get batch-mode processing even if there's no columnstore indexes present on the data.

Best Practices 108

Best Practices Servers Database Azure 108

SQL Performance

FEBRUARY 22, 2021

I would like to share a couple of recent examples that help illustrate how using deprecated SQL Server features continues to bite us. The system table sys.sysprocesses was replaced way back in SQL Server 2005 by a set of dynamic management views (DMVs), most notably sys.dm_exec_requests , sys.dm_exec_sessions , and sys.dm_exec_connections.

Latency 57

Latency Servers Monitoring Systems 57

Alex Podelko

OCTOBER 20, 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. I decided to publish a few parts here to see if anything triggers a discussion. It would be published as separate posts: – Introduction (a short teaser).

Performance Testing 100

Performance Testing Architecture Testing Performance 100

SQL Server According to Bob

JANUARY 28, 2018

Resource Manager – Database, File System, with ACID capabilities. Note: SQL Server can be a client using a linked server, allowing SQL Server to become an APP and/or an RM ). Once the connection to SQL Server is established the APP executes the odbc! Microsoft specific implementation for DTC using (OLE-TX).

Servers 40

Servers Azure Engineering Java 40

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). 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.

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C++ Database Servers Tuning 74

SQL Performance

AUGUST 11, 2021

Another is using a custom calculation that emulates the DATE_BUCKET function, which you can use in any version, edition, and flavor of SQL Server and Azure SQL Database. In my examples, I’ll use the sample database TSQLV5. You can find the script that creates and populates TSQLV5 here and its ER diagram here. DATE_BUCKET.

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Azure Code Database Servers 139

SQL Performance

DECEMBER 9, 2020

You can create supporting tables in the user database if needed. I tested my solutions in SQL Server 2019 Enterprise edition. SQL Server chose row mode processing for all previously shown solutions by default. There are a couple of ways to get SQL Server to use batch processing here. You can add hints as needed.

C++ 61

C++ Servers Testing Processing 61

Rigor

MARCH 20, 2018

I recently was asked the following question by an online retailer: “Why should I invest in monitoring the user experience when I already have monitoring for our database, infrastructure, app server, and network?”. This is a big deal when those resources often make up > 75% of the user experience. The Rise of Cloud Computing.

Monitoring 40

Monitoring Retail Ecommerce Infrastructure 40

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 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.

Servers 90

Servers Media Cache Storage 90

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.

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C++ Virtualization Servers Code 73

Smashing Magazine

JANUARY 15, 2019

The Green Web Foundation maintains an ever-growing database of web hosts who are either wholly powered by renewable energy or are at least committed to being carbon neutral. So, apart from powering servers with renewable energy, what else can web developers do about climate change? Server-Side Performance.

Website Performance 73

Website Performance Website Energy Performance 73

SQL Performance

OCTOBER 14, 2020

In my examples I’ll continue using the sample databases TSQLV5 and PerformanceV5. The issue is that even though SQL Server does support a short circuit concept at the physical processing level, there’s no assurance that it will evaluate the filter predicates in written order from left to right. Substitution/unnesting.

C++ 140

C++ Servers Code Efficiency 140

SQL Server According to Bob

JUNE 3, 2016

SQL Server 2016 ‘It Just Runs Faster’ A bold statement that any SQL Server professional can stand behind with confidence. Try SQL Server 2016 Today. The SQL Server Development team tasked several individuals with scalability improvements and real world testing patterns. – [link].

Hardware 40

Hardware Software Engineering Transportation Scalability 40

SQL Performance

JUNE 21, 2019

I've been teaching and writing about common SQL Server mistakes for many years. 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. SQL Server Agent alerts. This situation applies to on-premises SQL Server and IaaS.

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Servers Azure Hardware Database 49

SQL Performance

FEBRUARY 1, 2022

This is done to make managing operations in the transaction log easier for the log manager in SQL Server. You can’t specify how many VLFs are created by SQL Server when the database is first created or the log file automatically grows, but you can influence it.

Architecture 53

Architecture Servers Virtualization Database 53

SQL Server According to Bob

SEPTEMBER 26, 2016

When we released Always On Availability Groups in SQL Server 2012 as a new and powerful way to achieve high availability, hardware environments included NUMA machines with low-end multi-core processors and SATA and SAN drives for storage (some SSDs). As we moved towards SQL Server 2014, the pace of hardware accelerated.

Availability 40

Availability Servers Hardware Benchmarking 40

Percona

AUGUST 18, 2023

Why do you need multiple instances on the same server? Why not just create another database on the same instance? 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. ln -s /usr/local/Percona-Server-8.0.19-10-Linux.x86_64.ssl101/

Programming 83

Programming Servers Database Hardware 83

Percona

JANUARY 24, 2023

Some of the built-in features ( wal_compression ) have been there since 2016, and almost all backup tools do the WAL compression before taking it to the backup repository. Such “torn pages” are corruptions from the database point of view. This is generally referred to as “ partial page writes ” or “ torn pages.”

Database 115

Database Benchmarking Open Source Latency 115

SQL Performance

OCTOBER 14, 2020

In my examples I’ll continue using the sample databases TSQLV5 and PerformanceV5. The issue is that even though SQL Server does support a short circuit concept at the physical processing level, there’s no assurance that it will evaluate the filter predicates in written order from left to right. Substitution/unnesting.

C++ 52

C++ Servers Code Efficiency 52

Percona

FEBRUARY 2, 2023

Recall that logical replication works by using the PUB/SUB mode, where individual tables are published and are then subscribed by remotely connected databases/tables. The only real limitation is that one can only publish tables from a read-write server such as the PRIMARY. DML operations, such as INSERT, UPDATE, DELETE, TRUNCATE, etc.,

Games 88

Games Open Source Tuning Speed 88

SQL Performance

MARCH 20, 2020

We're mid-cycle between releases, where we're not yet hearing about any of the features planned for SQL Server vNext. In SQL Server 2016, STRING_SPLIT solved a long-missing gap in a language that, admittedly, was not intended for complicated string processing. And that is what I want to bring up today.

Database 109

Database Servers C++ AWS 109