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Oracle 18c

Oracle 18c – select from a flat file

By Franck Pachot

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This post is the first one from a series of small examples on recent Oracle features. My goal is to present them to people outside of Oracle and relational databases usage, maybe some NoSQL players. And this is why the title is “select from a flat-file” rather than “Inline External Tables”. In my opinion, the names of the features of Oracle Database are invented by the architects and developers, sometimes renamed by Marketing or CTO, and all that is very far from what the users are looking for. In order to understand “Inline External Table” you need to know all the history behind: there were tables, then external tables, and there were queries, and inlined queries, and… But imagine a junior who just wants to query a file, he will never find this feature. He has a file, it is not a table, it is not external, and it is not inline. What is external to him is this SQL language and what we want to show him is that this language can query his file.

18c runInstaller -silent

By Franck Pachot

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18c runInstaller -silent

By Franck Pachot

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18c runInstaller -silent

By Franck Pachot

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Oracle 18c preinstall RPM on RedHat RHEL

By Franck Pachot

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The Linux prerequisites for Oracle Database are all documented but using the pre-install rpm makes all things easier. Before 18c, this was easy on Oracle Enterprise Linux (OEL) but not so easy on RedHat (RHEL) where the .rpm had many dependencies on OEL and UEK.
Now that 18c is there to download, there’s also the 18c preinstall rpm and the good news is that it can be run also on RHEL without modification.

This came to my attention on Twitter:

18c: No Active Data Guard required (and detected) when only CDB$ROOT and PDB$SEED are opened in read-only

When you clone a PDB on the primary CDB, you want that the same is automatically done on the standby ones. Unfortunately, for this operation, the CDB must be opened read-only. In 12.1 even the PDB needed to be opened read-only (Ludovico Caldara reported this in his blog). This, as far as I know, was fixed in 12.2 where MRP reads the files without the need to have the PDB opened. But another problem comes with online cloning, as reported by Alain Fuhrer in his blog, where the CDB needs to be opened read-only with real-time apply. This again requires the Active Data Guard option, which is then mandatory to use all power from the multitenant option.

ADWC – System and session settings (DWCS lockdown profile)

By Franck Pachot

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The Autonomous Data Warehouse Cloud service is a PaaS managed service where we have a PDB and an ADMIN user which has most of the system privileges. For example, we have the privilege to change initialization parameters:
SQL> select * from dba_sys_privs where grantee=user and privilege like 'ALTER S%';
 
GRANTEE PRIVILEGE ADMIN_OPTION COMMON INHERITED
------- --------- ------------ ------ ---------
ADMIN ALTER SESSION YES NO NO
ADMIN ALTER SYSTEM YES NO NO

ADWC – connect from your premises

By Franck Pachot

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In the previous post about the Autonomous Data Warehouse Service, I’ve run queries though the Machine Learning Notebooks. But you obviously want to connect to it from your premises, with SQL*Net.

ADWC – the hidden gem: Zepplin Notebook

By Franck Pachot

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IMG_5339
In the previous blog posts I explained how to create, and stop/start the Autonomous Data Warehouse Cloud service. And I didn’t show yet how to connect to it. It is easy, from sqlplus or SQL Developer, or SQLcl.

But there’s something more exciting to run some SQL queries: the Oracle Machine Learning Notebooks based on Apache Zepplin. At first, I didn’t realize why the administration menu entry to create users in the ADWC service was named ‘Manage Oracle ML Users’, and didn’t realize that the ‘Autonomous Data Warehouse Cloud’ header was replaced by ‘Machine Learning’.

ADWC – a Docker container to start/stop Oracle Cloud services

By Franck Pachot

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In the previous post, I’ve explained how to start and stop the Autonomous Data Warehouse Cloud service from PSM (PaaS Service Manager). There’s a setup phase, and a run phase starting with service-start and ending with service-stop. And the setup is specific to an Oracle Cloud account, storing information in the local user home. You may want to run different setups, and even provide an easy way to start/stop an Oracle Cloud service without knowing the user, password and tenant name.

A Docker container is perfect to isolate this.