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Database Administration & Monitoring

Franck Pachot

DynamoDB: adding a Local covering index to reduce the cost

By | AWS, Cloud, Database Administration & Monitoring | No Comments

By Franck Pachot . This is a continuation on the previous post on DynamoDB: adding a Global Covering Index to reduce the cost. I have a DynamoDB partitioned on “MyKeyPart”,”MyKeySort” and I have many queries that retrieve a small “MyIndo001” attribute. And less frequent ones needing the large “MyData001” attribute. I have created a Global Secondary Index (GSI) that covers the same key and this small attribute. Now, because the index is prefixed by the…

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Franck Pachot

DynamoDB: adding a Global covering index to reduce the cost

By | AWS, Cloud, Database Administration & Monitoring | No Comments

By Franck Pachot . People often think of indexes as a way to optimize row filtering (“get item” faster and cheaper). But indexes are also about columns (“attribute projection”) like some kind of vertical partitioning. In relational (“SQL”) databases we often add more columns to the indexed key. This is called “covering” or “including” indexes, to avoid reading the whole row. The same is true in NoSQL. I’ll show in this post how, even when…

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Daniel Westermann

About temp_tablespaces in PostgreSQL

By | Database Administration & Monitoring | One Comment

There often is a discussion if tablespaces should be used in PostgreSQL. People used to work with Oracle are often a bit surprised by this discussion as there is no way around using tablespaces in that technology. PostgreSQL does not force you to use tablespaces at all and I am pretty sure that there are plenty of PostgreSQL installations out there that do not use them and never even considered using them and that is…

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Daniel Westermann

Collations in PostgreSQL – basics

By | Database Administration & Monitoring | No Comments

When you work with databases sooner or later you will need to get in touch witch collations. It might be that you never needed to think about it as initdb picked a value that just worked for you and nobody in your database ever tried to use a collation that is not available in your installation. Once someone is trying that or there is the requirement to use a specific collation from the beginning you…

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SQL Server: Collect Page Split events using Extended Event session

By | Database Administration & Monitoring, SQL Server | No Comments

Earlier this week someone tried to show me how to capture page split events using Extended Events (XE) but unfortunately, the demo failed. This is a good opportunity for me to refresh my knowledge about page split and set up a simple demo about this. Hopefully, this one will be working. It’s not necessarily a bad thing when a page split occurs. It’s a totally fine behavior when we INSERT a row in a table…

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Pascal Brand

After login as administrator to the WebLogic console, impossible to run administration action

By | Database Administration & Monitoring | No Comments

For a few weeks I was faced with a problem that I had never encountered before. On a Windows Server, browsing to the WebLogic Administration console, I was not able to do any modification or even check the monitoring screens. I always got a message that an error occurred without more explanation. After a new start of the WebLogic Administration Server, the error disappeared but was back after a day a a few hours. <An…

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Pascal Brand

WebLogic 12.2.1.4 software installation or upgrade, installs and configure Coherence cache in the domains

By | Database Administration & Monitoring | No Comments

We are using silent installation to install WebLogic Server software based on a response file with “INSTALL_TYPE=WebLogic Server” but it looks like the coherence server is installed becuase when we start the WebLogic Server, the following can be seen in the WebLogic log files: Oracle Coherence Version 12.2.1.4.0 Build 74888 Grid Edition: Development mode Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved. 2020-01-03 14:18:45.334/42.467 Oracle Coherence GE 12.2.1.4.0 (thread=[ACTIVE] ExecuteThread: ‘5’ for…

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Stephane Biehler

Java 1.8 Utility classes: XML, ZIP, BufferedImage and Download

By | Database Administration & Monitoring | No Comments

When I write code, I usually need some utility classes to ease the development. So here I will share my most used classes. Hope this will help you as well! XML store and load I strongly use XML for storing configurations or even data, so I made an helper which can store and load any classes (with annotations) as XML, using generics import java.io.File; import javax.xml.bind.JAXBContext; import javax.xml.bind.JAXBException; import javax.xml.bind.Marshaller; import javax.xml.bind.Unmarshaller; /** * Utility…

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Jérôme Dubar

Speed up datapump export for migrating big databases

By | Database Administration & Monitoring, Database management, Hardware & Storage, Oracle | 3 Comments

Introduction Big Oracle databases (several TB) are still tough to migrate to another version on a new server. For most of them, you’ll probably use RMAN restore or Data Guard, but datapump is always a cleaner way to migrate. With datapump, you can easily migrate to a new filesystem (ASM for example), rethink your tablespace organization, reorganize all the segments, exclude unneeded components, etc. All of these tasks in one operation. But datapump export can…

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