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Oracle disables your multitenant option when you run on EC2

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 per processor, which means per-core because Oracle doesn’t count the core factor when your Intel processors are in AWS Cloud (according to the Authorized Cloud Environments paper)?

DynamoDB: adding a Local covering index to reduce the cost

By Franck Pachot

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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 partition key, I can create a Local Secondary Index (LSI) to do the same. But there are many limitations. The first one is that I cannot add a local index afterwards. I need to define it at the table creation.

Drop table

Here I am in a lab so that I can drop and re-create the table. In real live you may have to create a new one, copy the items, synchronize it (DynamoDB Stream),…

DynamoDB: adding a Global covering index to reduce the cost

By Franck Pachot

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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 an index is not required to filter the items, because the primary key partitioning is sufficient, we may have to create a secondary index to reduce the cost of partial access to the item. Here is an example with AWS DynamoDB where the cost depends on I/O throughput.

Developing Applications with CockroachDB… end-to-end example with SpringBoot, Java, Hibernate, Gradle

overview

Application development frameworks like SpringBoot have done a good job a giving developers a quick start to developing applications with Java. Layering object-relational mapping to SQL to remove proprietary syntax has further simplified the development of database applications.

CockroachDB allows developers to take advantage in the evolution of globally distributed data with a simple SQL interface. But each database can bring it’s own specific syntax and cause developers to hesitate when getting started with a new database.

How do you get started?

Oracle 20c SQL Macros: a scalar example to join agility and performance

By Franck Pachot

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Let’s say you have a PEOPLE table with FIRST_NAME and LAST_NAME and you want, in many places of your application, to display the full name. Usually my name will be displayed as ‘Franck Pachot’ and I can simply add a virtual column to my table, or view, as: initcap(FIRST_NAME)||’ ‘||initcap(LAST_NAME). Those are simple SQL functions. No need for procedural code there, right? But, one day, the business will come with new requirements. In some countries (I’ve heard about Hungary but there are others), my name may be displayed with last name… first, like: ‘Pachot Franck’. And in some context, it may have a comma like: ‘Pachot, Franck’.

There comes a religious debate between Dev and Ops:

Demystifying JSON with CockroachDB… Import, Index, and Computed Columns

Overview

Recently, I created and delivered an "Advanced Developer Workshop" for CockroachLabs. One of the topics dove into how to ingest and use JSON data.

Like many databases, CockroachDB has the ability to use JSON data type for columns within a table. Basically, you insert a JSONB object into a row, and then can filter and extract the desired data with SQL. The following simple example shows how this is done:

So it is pretty straight forward to use JSONB objects within tables, but how do you load those HUGE json files into CockroachDB?

Running SQL Server on the Oracle Free tier

By Franck Pachot

The Oracle Cloud is not only for Oracle Database. You can create a VM running Oracle Linux with full root access to it, even in the free tier: a free VM that will be always up, never expires, with full ssh connectivity to a sudoer user, where you are able to tunnel any port. Of course, there are some limits that I’ve detailed in a previous post. But that is sufficient to run a database, given that you configure a low memory usage. For Oracle Database XE, Kamil Stawiarski mentions that you can just hack the memory test in the RPM shell script.

Running SQL Server on the Oracle Free tier

By Franck Pachot

The Oracle Cloud is not only for Oracle Database. You can create a VM running Oracle Linux with full root access to it, even in the free tier: a free VM that will be always up, never expires, with full ssh connectivity to a sudoer user, where you are able to tunnel any port. Of course, there are some limits that I’ve detailed in a previous post. But that is sufficient to run a database, given that you configure a low memory usage. For Oracle Database XE, Kamil Stawiarski mentions that you can just hack the memory test in the RPM shell script.

Sharing my screen to the web (from Oracle free tier compute instance) using tmux and gotty

Sharing my screen to the web (from Oracle free tier compute instance) using tmux and gotty

For a long time, I use tmux for my live demos because I can multiplex my screen between my laptop and the beamer, I can show several panes, and I can script my commands using send-keys. I also use tmux to keep a stateful work environment which I run on my Oracle Cloud always free tier Compute Instance, which is 100% free and 100% available, and 100% accessible

Sharing my screen to the web (from Oracle free tier compute instance) using tmux and gotty

Sharing my screen to the web (from Oracle free tier compute instance) using tmux and gotty

For a long time, I use tmux for my live demos because I can multiplex my screen between my laptop and the beamer, I can show several panes, and I can script my commands using send-keys. I also use tmux to keep a stateful work environment which I run on my Oracle Cloud always free tier Compute Instance, which is 100% free and 100% available, and 100% accessible