Tag: row

Feed: Planet big data. Author: Guest Blogger. by Lixun Zhang (Data Scientist), Ye Xing (Senior Data Scientist) and Tao Wu (Principal Data Scientist Manager), all at Microsoft Editor's Note: To learn more about migrating from SAS to R, there will be a live webinar presented by Lixun and Ye tomorrow (Tuesday, November 15). Register to attend the webinar here. R has been gaining in popularity among data professionals in recent years in industries such as financial services, as shown for example in this survey from executive search firm Burtch Works. In this blog post we share some key considerations in migrating ... Read More

Feed: Planet PostgreSQL. It’s a common misconception that high volume read-write workloads in PostgreSQL inevitably causes database inefficiency. We’ve heard of cases where users encounter slowdowns doing only a few hundred writes per second and turn to systems like Dynamo or Cassandra out of frustration. However PostgreSQL can handle these workloads without a problem as long as it is configured correctly. The problems stem from what’s known as “bloat,” a phenomenon of PostgreSQL and other MVCC databases which causes increased space usage and decreased performance. We’ll see how autovacuum, a tool to combat bloat, is typically misunderstood and misconfigured. By ... Read More

Feed: Databasejournal.com - Feature Database Articles. Author: . Oracle 12.1 provides an interesting performance enhancement, the in-memory column store, that can increase performance by reducing physical I/O load by making tables memory-resident (to simplify the description somewhat). Along with the in-memory access to table data Oracle has introduced a new optimization called "Vector Transformation, including Vector Optimization" for in-memory operations. Even when this new optimization isn't in use there are new code paths to take advantage of this technology. As a result execution plans can change; let's look at an example originally provided by Jonathan Lewis that illustrates this. Two ... Read More

Feed: Planet PostgreSQL. PG Phriday: Broken Parts October 21st, 2016 | Published in Database, Tech Talk | No Comments Partitioning tables in Postgres can be an extremely risky endeavor. Unfortunately on many larger systems, it’s also essentially a requirement; the maximum size of a Postgres table is 32TB. This isn’t just because converting an existing table to a series of partitions is expensive or time consuming. We must consider how the query planner will react to the partitioned version of a table. There’s also the very real risk we will (or already have) implement flaws in the trigger or constraint ... Read More

Feed: SQL Server Customer Advisory Team. Author: Dimitri Furman. Reviewed by: Steven Green, Peng Song, Xiaochen Wu, Kun Cheng, Sanjay Mishra Introduction Database migration from SQL Server to Azure SQL Database is a process that many organizations must implement as they move to Azure public cloud. This article is a guide that describes one specific implementation path for the migration process, that has been commonly used by Microsoft customers. To aid others in the same task, in this article we present lessons learned, recommendations, examples, caveats, potential issues, solutions, and workarounds. A sample PowerShell script that automates some migration steps ... Read More

Feed: Planet MySQL. Author: Gabriela D'Ávila. The Theory Generated Columns is a feature released on MySQL 5.7. They can be used during CREATE TABLE or ALTER TABLE statements. It is a way of storing data without actually sending it through the INSERT or UPDATE clauses in SQL. The database resolves what the data will be. There are two types of Generated Columns: Virtual and Stored. They work with: mathematical expressions (product_price * quantity) built-in functions (RIGHT(), CONCAT(), FROM_UNIXTIME(), JSON_EXTRACT()) literals (“2”, “new”, 0) Besides that, they can be indexed but they don’t allow subqueries in it.A Generated Column works within ... Read More

This will be a multi-part series covering various areas of failover for MySQL.  This first installment will primarily look at some design considerations, which you can then apply to your own environment in your own way.  The concepts presented here are merely suggestions and not out-right “how-to”.   Every company has specific technologies or skill-sets in house that may drive a solution one way or another.  Future installments will cover our latest MySQL Utilities 1.6.4 GA release set of tools which those utilities can be downloaded here. Then  review of our in-development Group Replication system v.0.8.0 with its latest labs release ... Read More