Tag: row

Feed: Planet PostgreSQL. When I was in the market for an EV, one of the things I wondered about was how far I would be able to go outside the city before I had to charge it. Having a number for the range isn’t enough to know offhand whether I’d be able to reach a particular destination. So I wanted to make the range more obvious in my EV guide by visualising vehicle range on a map. The trivial solution is to use range as a radius and show a circle: But of course, that’s going to be massively inaccurate ... Read More

Feed: SAS Blogs. Author: Chevell Parker. Introduction Generating a word cloud (also known as a tag cloud) is a good way to mine internet text. Word (or tag) clouds visually represent the occurrence of keywords found in internet data such as Twitter feeds. In the visual representation, the importance of each keyword is denoted by the font size or font color. View more Problem Solvers posts You can easily generate Word clouds by using the Python language. Now that Python has been integrated into the SAS® System (via the SASPy package), you can take advantage of the capabilities of both ... Read More

Feed: Planet MySQL; Author: Federico Razzoli; Stage IV shows what will happen if bugs decide to attack humanityHint: it will not be good for us Foreign keys are a controversial topic. Some developers love them, because they make the database more robust. Some DBAs forbid them, because they propagate locks, increase the number of reads, and pollute the buffer pool. This article doesn’t discuss the foreign key problem globally. It is about the MySQL and MariaDB implementations: more specifically, it is a list of the most important bugs and limitations that involve foreign keys. For each bug you can see ... Read More

Feed: Planet PostgreSQL. With PostgreSQL 12 the generated columns are now supported natively. Until the version Postgresql 11 it were possible to have generated columns using a trigger. In this post we’ll see how to configure a generated column via trigger and natively then we’ll compare the performances of both strategies. Generated columns A generated column can be stored or virtual. A stored column calculates the generated value from other columns of the table and stores the value during the INSERT and UPDATE operations. A virtual column is computed on the fly when the data is retrieved from the table ... Read More

Feed: R-bloggers. Author: Carlos Biagolini-Jr.. [This article was first published on R-posts.com, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here) Want to share your content on R-bloggers? click here if you have a blog, or here if you don't. This tutorial illustrates how to use the bwimge R package (Biagolini-Jr 2019) to describe patterns in images of natural structures. Digital images are basically two-dimensional objects composed by cells (pixels) that hold information of the intensity of three color channels (red, green and blue). For some file formats (such as png) another channel ... Read More

Feed: Planet MySQL; Author: MySQL Server Dev Team; The MySQL Development team is proud to announce a new version of the MySQL Shell with the following major improvements: Migration to Python 3 Built-in thread reports Ability to use an external editor Ability to execute system commands within the shell Admin API Improvements: New options to log all the SQL used on the different operations Support for IPv6 in InnoDB Clusters New function to reset the InnoDB Cluster recovery accounts General maintenance and bug fixing Python 3 Migration Due to the coming end-of-life (EOL) for Python 2.7 by end of this ... Read More

Feed: Planet PostgreSQL. We recently had the chance to help a customer with some IO related issues that ended up being unconfigured checkpoints. Something that may not always be obvious but can actually be somewhat common.Let's start with how things roughly work. Postgres smallest IO unit is a disk block that is 8kb (by default). Each time postgres needs a new block it will fetch it from the disks and load it to an area in RAM called shared_buffers. When postgres needs to write, it does it in the same manner:Fetches the block(s) from the disks if the block is ... Read More

Feed: James Serra's Blog. Author: James Serra. Introduced in April 2019, Databricks Delta Lake is, in short, a transactional storage layer that runs on top of cloud storage such as Azure Data Lake Storage (ADLS) Gen2 and adds a layer of reliability to organizational data lakes by enabling many features such as ACID transactions, data versioning and rollback. It does not replace your storage system. It is a Spark proprietary extension and cloud-only. It has been open sourced and the code can be found here. Full documentation is at the Delta Lake Guide. It’s real easy to use. When writing ... Read More

Feed: Planet MySQL; Author: Ramesh Sivaraman; This blog post will help you configure a 3-node Percona XtraDB Cluster using a binary tarball on your local machine. Configuration files are auto-generated with mostly default configurations except for port/IP address details. The tool has the handy script to create configuration files and start multiple Percona XtraDB Cluster nodes on the fly, helping you to start PXC quickly without spending time on startup configuration as well as avoid using any virtual environments.  The script is available in the percona-qa github project. Currently, this script supports PXC binary tarball distributions only.You can download the ... Read More

Feed: Planet MySQL; Author: MySQL High Availability; Up until MySQL 8.0.18, the slave executes replicated transactions without checking privileges. It does so to be able to apply everything that its upstream server (the master) tells it to. In practice this means that the slave fully trusts its master. However, there may be setups in which changes cross a security boundary between master and slave, and therefore the slave may need to enforce data access constraints for the replicated stream. In that case it is helpful to apply the changes coming from upstream in a more restricted security context. From 8.0.18 ... Read More