Oracle Database as our consultants live it every day: installation and patching, upgrades, RMAN backup and recovery, Data Guard, RAC, performance tuning, multitenant, licensing, and engineered systems such as ODA and Exadata.
What is Linked server ? Now a days in each company we have different applications and each one of them have different needs in term of databases support. When data exists on multiple databases the management become a little bit hard. For exemple moving some data from an Oracle database to a SQL Server database is not easy. A linked…
By Franck Pachot . J’essaie quelque chose de nouveau. Je publie beaucoup en anglais (blog, articles, présentations) mais cette fois quelque chose de 100% francophone. En sortant du confinement, on reprend les transports (train, voiture,…) et c’est l’occasion de se détendre en musique mais aussi de s’informer avec des podcasts. J’ai l’impression que c’est un format qui a de l’avenir:…
By Franck Pachot . The FETCH FIRST … ROWS ONLY syntax arrived in Oracle 12c and is much more convenient than using a subquery with ‘ORDER BY’ wrapped in a “WHERE ROWNUM < …” around it. But as I mentioned in a previous post it required the FIRST_ROWS() hint to get correct estimations. In SQL you don’t want to overload…
By Franck Pachot . I’ll reference Alex DeBrie article “SQL, NoSQL, and Scale: How DynamoDB scales where relational databases don’t“, especially the paragraph about “Why relational databases don’t scale”. But I want to make clear that my post here is not against this article, but against a very common myth that even precedes NoSQL databases. Actually, I’m taking this article…
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 [grid@cloud ~]$ asmcmd…
I had the opportunity to participate to POUG day 1 and wanted through this blog to share some of my feedback on the interesting sessions I could follow. First of all, I would like to mention the great introduction done by the staff team and the great organization. POUG staff team could adapt to the coronavirus situation and organized excellent…
By Mouhamadou Diaw When dealing with cascading or far sync in a Data Guard environment, it is important to understand how to configure the RedoRoutes property. By default, a primary database sends redo to each transport destination that is configured in the destination. We can create more complex transport topology, depending of our environment, using the RedoRoutes property. Basically the…
By Franck Pachot . Oracle Enterprise Linux (OEL) is a Linux distribution which is binary compatible with Red Hat Enterprise Linux (RHEL). However, unlike RHEL, OEL is open source, free to download, free to use, free to distribute, free to update and gets free bug fixes. And there are more frequent updates in OEL than in CentOS, the free base…
The global_name in an oracle database has a direct impact on the Golden Gate Extract process registration we need to do when we create an Integrated Extract. In my example below, I use Oracle GoldenGate MicroServices architecture but the same behaviour occurs with Oracle GoldenGate Classic architecture. Let’s start with the creation of the Extract process by clicking on…
Introduction Cloud, Cloud, Cloud. Everyone is talking about the Cloud but a lot of people are still in the fog with Cloud technologies. Let’s talk about basic features of the Oracle Cloud, called OCI for Oracle Cloud Infrastructure. What is really OCI? OCI is physically a lot of servers in datacenters all around the world. These servers are not very…
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.…
By Franck Pachot . Sorting data is an expensive operation and many queries declare an ORDER BY. To avoid the sort operation you can build an index as it maintains a sorted structure. This helps with Top-N queries as you don’t have to read all rows but only those from a range of index entries. However, indexes are sorted by…
