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Displaying posts with tag: postgresql (reset)
How to limit the SQL query result set to Top-N rows only

Introduction In this article, we are going to see how we can limit the SQL query result set to the Top-N rows only. Limiting the SQL result set is very important when the underlying query could end up fetching a very large number of records, which can have a significant impact on application performance. Why limit the number of rows of a SQL query? Fetching more data than necessary is the number one cause of data access performance issues. When a given business use case is developed, the amount of data available... Read More

The post How to limit the SQL query result set to Top-N rows only appeared first on Vlad Mihalcea.

SQL ORDER BY RANDOM

Introduction In this article, we are going to see how we can sort an SQL query result set using an ORDER BY clause that takes a RANDOM function provided by a database-specific function. This is a very handy trick, especially when you want to shuffle a given result set. Note that sorting a large result set using a RANDOM function might turn out to be very slow, so make sure you do that on small result sets. If you have to shuffle a large result set and limit it afterward, then it’s... Read More

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2019 Open Source Database Report: Top Databases, Public Cloud vs. On-Premise, Polyglot Persistence

Ready to transition from a commercial database to open source, and want to know which databases are most popular in 2019? Wondering whether an on-premise vs. public cloud vs. hybrid cloud infrastructure is best for your database strategy? Or, considering adding a new database to your application and want to see which combinations are most popular? We found all the answers you need at the Percona Live event last month, and broke down the insights into the following free trends reports:

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Introducing Tungsten Replicator (AMI): The High Performance Replication Engine For MySQL, MariaDB & Percona Server

Discover Tungsten Replicator (AMI) – the replication engine for MySQL, MariaDB & Percona Server, including Amazon RDS MySQL and Amazon Aurora We’re excited to announce the availability on the Amazon Marketplace of the new Tungsten Replicator (AMI). Tungsten Replicator (AMI) is a replication engine that provides high-performance and improved replication functionality over the native MySQL replication solution and provides an ability to apply real-time MySQL data feed into a range of analytics and big data databases. Tungsten Replicator (AMI) builds on the well-established, commercial stand-alone product Tungsten Replicator and offers the exact same functionality, but with the convenience that comes with an ad-hoc online service: cost-effective and rapid, automated deployment. Target Databases Available as of Today

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Pythian will be at Percona Live 2019 – Join us in Austin, Texas!

Percona Live provides the open source database community with an opportunity to discover and discuss the latest open source trends, technologies, and innovations. The conference includes the best and brightest innovators and influencers in the open source database industry.

This year, Percona Live is being held at the Hyatt Regency in Austin, Texas from May 28-30, 2019.

Pythian is proud to be a Silver Sponsor this year, with a full force of our technical experts speaking on a variety of subjects and technologies. These are sessions you won’t want to miss!

If you’re attending, make sure you swing by our booth and meet the Pythian crew. We’ll be happy to answer any questions you have about open source, cloud or anything data related. Our speakers will also be covering the event on social media and we’ll recap the event and their talks here on the Pythian …

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Benchmark ClickHouse Database and clickhousedb_fdw

In this research,  I wanted to see what kind of performance improvements could be gained by using a ClickHouse data source rather than PostgreSQL. Assuming that I would see performance advantages with using ClickHouse, would those advantages be retained if I access ClickHouse from within postgres using a foreign data wrapper (FDW)? The FDW in question is clickhousedb_fdw – an open source project from Percona!

The database environments under scrutiny are PostgreSQL v11, clickhousedb_fdw and a ClickHouse database. Ultimately, from within PostgreSQL v11, we are going to issue various SQL queries routed through our clickhousedb_fdw to the ClickHouse database. Then we’ll see how the FDW performance compares with those same queries executed in native PostgreSQL and native ClickHouse.

Clickhouse Database

ClickHouse is an open source column based database management system which can achieve performance of between 100 and …

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Percona Universities in South America Next Week

There’s just one week to go before the first of this year’s Percona University events in South America. We’re really pleased with the lineup for all three events. We’re also incredibly happy with the response that we have had from the community. While we realize that a free event is… well… free… you are still giving up your time and travel. We place great value on that and we’re making sure that you’ll be hearing quality technical talks from Percona and our guest speakers. Most of the talks will be presented in Spanish – Portuguese in Brazil – although slides will be made available in English.

In fact, the events have been so popular that it’s quite possible that by the time you read this we’ll be operating a wait list for Montevideo

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How to implement a database job queue using SKIP LOCKED

Introduction In this article, we are going to see how we can implement a database job queue using SKIP LOCKED. I decided to write this article while answering this Stack Overflow question asked by Rafael Winterhalter. Since SKIP LOCKED is a lesser-known SQL feature, it’s a good opportunity to show you how to use it and why you should employ it, especially when implementing a job queue task. Domain Model Let’s assume we have the following Post entity which has a status Enum property looking as follows: The PostStatus Enum encapsulates the... Read More

The post How to implement a database job queue using SKIP LOCKED appeared first on Vlad Mihalcea.

Upcoming Webinar Wed 4/10: Extending and Customizing Percona Monitoring and Management

Please join Percona’s Product Manager, Michael Coburn, as he presents his talk Extending and Customizing Percona Monitoring and Management on April 10th, 2019 at 10:00 AM PDT (UTC-7) / 1:00 PM EDT (UTC-4).

Register Now

Do you already run stock PMM in your environment and want to learn how you extend the PMM platform? If so, come learn about:

1. Dashboard Customizations
* How to create a custom dashboard from existing graphs, or build Cross Server Dashboards
2. External Exporters – Monitor any service, anywhere!
* …

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How does a relational database execute SQL statements and prepared statements

Introduction In this article, we are going to see how a relational database executes SQL statements and prepared statements. SQL statement lifecycle The main database modules responsible for processing a SQL statement are: the Parser, the Optimizer, the Executor. A SQL statement execution looks like in the following diagram. Parser The Parser checks the SQL statement and ensures its validity. The statements are verified both syntactically (the statement keywords must be properly spelled and following the SQL language guidelines) and semantically (the referenced tables and column do exist in the database). During... Read More

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