SQL Performance

APRIL 17, 2020

The ALTER TABLE. It is certainly more convenient than the alternative: Creating a new table and migrating the data each time a change is necessary. When we ask SQL Server to change some aspect of a column's definition, it needs to check that the existing data is compatible with the new definition. Metadata-Only Changes.

Servers 63

Servers Database Testing Efficiency 63

SQL Performance

MAY 16, 2019

The word “traditional” there excludes columnstore and memory-optimized (‘Hekaton’) clustered tables). For the conditions that apply when the target table is a heap, see the previous article in this series. For the conditions that apply when the target table is a heap, see the previous article in this series.

Cache 67

Cache Servers Testing Storage 67

SQL Performance

JUNE 5, 2019

One of the more perplexing problems to troubleshoot in SQL Server can be those related to memory grants. Some queries need more memory than others to execute, based on what operations need to be performed (e.g. If it underestimates memory, then you can see spills in tempdb. The Sales.Orders table has about 4.6

Servers 41

Servers Cache Database Metrics 41

SQL Performance

APRIL 5, 2019

The IGNORE_DUP_KEY option for unique indexes specifies how SQL Server responds to an attempt to INSERT duplicate values: It only applies to tables (not views) and only to inserts. The following script creates a temporary table with a million rows. DROP TABLE IF EXISTS #Data ; GO. DROP TABLE IF EXISTS #Data ; GO.

Storage 53

Storage Servers Engineering Testing 53

SQL Performance

OCTOBER 7, 2020

The canonical example of a plan operator that can rewind is the lazy Table Spool. The documentation says only the following operators can rewind: Table Spool. Table-valued Function. Table-valued functions use a table variable, which can be used to cache and replay results in suitable circumstances.

Servers 106

Servers Cache Azure Performance 106

Scalegrid

MAY 13, 2020

Greenplum Database is a massively parallel processing (MPP) SQL database that is built and based on PostgreSQL. It can scale towards a multi-petabyte level data workload without a single issue, and it allows access to a cluster of powerful servers that will work together within a single SQL interface where you can view all of the data.

Big Data 321

Big Data Database Artificial Intelligence Open Source 321

Percona

SEPTEMBER 1, 2023

MySQL server performance can sometimes be perplexing, and if you’ve ever wondered about the role of triggers in influencing your MySQL server’s memory allocation, this post is for you. These events, known as trigger events, can include actions like inserting, updating, or deleting records in database tables.

Cache 59

Cache Database Games Healthcare 59

SQL Performance

MAY 1, 2019

That said, this article is purely concerned with providing new details about minimal logging when bulk loading traditional (not “memory-optimized”) heap tables using INSERT.SELECT. Tables with a b-tree clustered index will be covered separately in my next post. Heap tables. An Exception to the Rule. TestHeap. (

Servers 47

Servers Database Testing Performance 47

Percona

JULY 1, 2023

It efficiently manages read and write operations, optimizes data access, and minimizes contention, resulting in high throughput and low latency to ensure that applications perform at their best. This post was originally published in July 2018 and was updated in July 2023. What are the differences between Aurora and RDS? What is Amazon RDS?

AWS 52

AWS Database Serverless Storage 52

SQL Performance

MARCH 30, 2021

This five-part series takes a deep dive into the way SQL Server row mode parallel plans start up. The fundamentals of row mode parallel execution haven’t changed since SQL Server 2005, so the following discussion is broadly applicable. The query optimizer produces a single compiled plan for a batch.

Cache 98

Cache Servers Operating System Processing 98

SQL Performance

NOVEMBER 22, 2019

The optimizer must consider that the work involved saves more than it costs. The downside is the extra sorting cost may dissuade the optimizer from choosing the spool option at all. SQL Server does not support parallel inserts to a b-tree index. The TransactionHistory table is only scanned once. Cost assessment.

Servers 77

Servers Cache Database Performance 77

Highly Scalable

MARCH 1, 2012

First, we should note that SQL and relational model in general were designed long time ago to interact with the end user. This user-oriented nature had vast implications: The end user is often interested in aggregated reporting information, not in separate data items, and SQL pays a lot of attention to this aspect.

Database 279

Database Ecommerce Efficiency Engineering 279

Scalegrid

AUGUST 15, 2019

Since then, however, many new options have emerged to help you optimize your MongoDB management and we thought we’d share our updates. Since then, however, many new options have emerged to help you optimize your MongoDB management and we thought we’d share our updates. We left those at the end of this post for your review.

Database 40

Database Servers Monitoring Availability 40

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.

Efficiency 40

Efficiency Code Servers Cache 40