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Alain Fuhrer

Magic Upgrade to 21c with Replay Upgrade Feature

By | Database Administration & Monitoring | No Comments

Last week I did some upgrade tests from 19c to 21c. The plan was to copy a 19c PDB to a CDB 21c using Online Clone and then upgrade it to 21c. I have done this many times for 19c as well and just wanted to verify that it still worked with 21c. Clone PDB to 21c CDB Since it is a LAB, I gave the user SYSTEM in the CDB19c the appropriate duplicate permissions…

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Clemens Bleile

Creating an Oracle Snapshot Copy PDB on top of ASM

By | Oracle | No Comments

Creating a snapshopt copy Pluggable Database (PDB) on top of Automatic Storage Management (ASM) is not possible, because you need to have a filesystem which supports sparse files. According the following MOS-Note sparse files are supported on Automatic Storage Management Cluster File System (ACFS) since 12.2.: 12.2 Oracle ACFS Sparse Files Enhancements (Doc ID 2200264.1) However, I thought it is more fun to create a PDB Snapshot Copy on a XFS-filesystem, which I wanted to…

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Jérôme Dubar

Is it possible to switch a service between 2 pluggable databases?

By | Database Administration & Monitoring, Database management, Oracle | No Comments

Introduction In an Oracle database, services have multiple purposes: identifying group of users prior authenticating them enabling/disabling access to a database for particular groups managing preferred nodes on a RAC configuration redirecting users to the primary after a switchover/failover when using Data Guard or Dbvisit Standby redirecting read only connections to Standby database with Active Guard option A customer asked me if services could be used for switching between PDBs without modifying client’s connexion, for…

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Christian Weinfurtner

Oracle 21c: Blockchain Tables

By | Database Administration & Monitoring, Database management, Enterprise content management, Oracle | No Comments

Oracle Blockchain Tables With Oracle Database 20c/21c the new feature Oracle Blockchain Tables has been introduced. Blockchain Tables enable Oracle Database users to create tamper-resistant data management without distributing a ledger across multiple parties. Database security can be improved by using Blockchain Tables to avoid user fraud and administrator fraud as well. One of the main characteristics of Oracle Blockchain Tables is that you can only append data. Table rows are chained using a cryptographic…

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Oracle Team

Oracle ACFS: “du” vs. “df” and “acfsutil info”

By | Oracle | 2 Comments

By Franck Pachot . This is a demo about Oracle ACFS snapshots, and how to understand the used and free space, as displayed by “df”, when there are modifications in the base parent or the snapshot children. The important concept to understand is that, when you take a snapshot, any modification to the child or parent will [[email protected] ~]$ asmcmd lsdg DATAC1 State Type Rebal Sector Logical_Sector Block AU Total_MB Free_MB Req_mir_free_MB Usable_file_MB Offline_disks Voting_files…

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Open source Team

Some myths about PostgreSQL vs. Oracle

By | Oracle, Postgres | One Comment

By Franck Pachot . I originally wrote this as a comment on the following post that you may find on internet: https://www.2ndquadrant.com/en/blog/oracle-to-postgresql-reasons-to-migrate/ but my comment was not published (many links in it… I suppose it has been flagged as spam?) so I put it there. You should never take any decision on what you read on the internet without verifying. It is totally valid to consider a move to Open Source databases, but doing it…

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Oracle Team

What is a serverless database?

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

By Franck Pachot . After reading the https://cloudwars.co/oracle/oracle-deal-8×8-larry-ellison-picks-amazons-pocket-again/ paper, I am writing some thoughts about how a database can be serverless and elastic. Of course, a database needs a server to process its data. Serverless doesn’t mean that there are no servers. Serverless as not waiting for server provisioning The first idea of “serverless” is about provisioning. In the past when a developer required a new database to start a new project she had to…

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Oracle Team

Oracle disables your multitenant option when you run on EC2

By | Cloud, Oracle | 12 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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Oracle Team

ATP vs ADW – the Autonomous Database lockdown profiles

By | Cloud, Oracle | No Comments

By Franck Pachot . The Oracle database has always distinguished two types of workloads: transactional (OLTP) and datawarehouse (VLDB, DWH, DSS, BI, analytics). There is the same idea in the managed Oracle Cloud with two autonomous database services. To show how this is old, here is how they were defined in the Oracle7 Tuning Book: The definition has not changed a lot. But the technology behind DSS/DWH has improved. Now, with In-Memory Column Store, Smart…

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Oracle Team

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

By | Oracle | One Comment

By Franck Pachot . 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….

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