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Franck Pachot

Franck Pachot

AWS Aurora IO:XactSync is not a PostgreSQL wait event

By | AWS, Postgres | No Comments

By Franck Pachot . In AWS RDS you can run two flavors of the PostgreSQL managed service: the real PostgreSQL engine, compiled from the community sources, and running on EBS storage mounted by the database EC2 instance, and the Aurora which is proprietary and AWS Cloud only, where the upper layer has been taken from the community PostgreSQL. The storage layer in Aurora is completely different. In PostgreSQL, as in most RDBMS except for exclusive…

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Franck Pachot

AWS Certified Database Specialty (DBS-C01)

By | AWS, Cloud | One Comment

Here is my feedback after preparing and passing the AWS Database Specialty certification. There are tips about the exam but also some thoughts that came to my mind during the preparation when I had to mind-shift from a multi-purpose database system to purpose-built database services. Exam Availability This exam was in beta between last December/January and then was planned for production starting April 6, 2020. I initially planned to take the exam this first day…

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Franck Pachot

티베로 – The most compatible alternative to Oracle Database

By | Oracle | 6 Comments

By Franck Pachot . Do you remember that time where we were able to buy IBM PC clones, cheaper than the IBM PC but fully compatible? I got the same impression when testing Tibero, the TmaxSoft relational database compatible with the Oracle Database. Many Oracle customers are looking for alternatives to the Oracle Database, because of unfriendly commercial and licensing practices, like forcing the usage of expensive options or not counting vCPU for licensing. Up…

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Franck Pachot

Oracle Support: Easy export of SQL Testcase

By | Oracle | No Comments

By Franck Pachot . Many people complain about the quality of support. And there are some reasons behind that. But before complaining, be sure that you provide all information. Because one reason for inefficient Service Request handling is the many incomplete tickets the support engineers have to manage. Oracle provides the tools to make this easy for you and for them. Here I’ll show how easy it is to provide a full testcase with DBMS_DIAG….

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Franck Pachot

“Segment Maintenance Online Compress” feature usage

By | Oracle | No Comments

By Franck Pachot . On Twitter, Ludovico Caldara mentioned the #licensing #pitfall when using the Online Partition Move with Basic Compression. Those two features are available in Enterprise Edition without additional option, but when used together (moving online a compressed partition) they enable the usage of Advance Compression Option: Will it be reflected in dba_feature_usage_statistics? — Niels Jespersen (@njesp) April 19, 2020 And there was a qustion about detection of this feature. I’ll show how…

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Franck Pachot

Find the SQL Plan Baseline for a plan operation

By | Oracle | No Comments

By Franck Pachot . If you decide to capture SQL Plan Baselines, you achieve plan stability by being conservative: if the optimizer comes with a new execution plan, it is loaded into the SQL Plan Management base, but not accepted. One day, you may add an index to improve some queries. Then you should check if there is any SQL Plan Baseline for queries with the same access predicate. Because the optimizer will probably find…

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Franck Pachot

Oracle recovery concepts

By | Oracle | No Comments

I’ve published a while ago a twitter thead on some Oracle recovery concepts. For those who are not following twitter, I’m putting the whole thread here:   🔴⏬ Here I start a thread about some Oracle Database concepts. We will see how far it goes - all questions/comments welcome. 🔴⏬ A database (or DBMS - database management system) stores (for short and long term) and manipulates (from many concurrent users/devices) your #data. 🔴⏬ #data is logically structured (tablespaces, schemas, tables, columns, datatypes,…

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Franck Pachot

Oracle disables your multitenant option when you run on EC2

By | Cloud, Oracle | 6 Comments

I have installed Oracle 19.6 on an EC2 for our Multitenant Workshop training. And of course, during the workshop we create a lot of PDBs. If you don’t have paid for the Enterprise Edition plus the Multitenant Option you can create at most 3 pluggable database. But with this option you can create up to 252 pluggable databases. Does it worth the price, which according to the public price list is USD 47,500 + 17,500…

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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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