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Database

Everything our consultants learn while running databases for customers: Oracle, PostgreSQL, SQL Server, MySQL, MariaDB, MongoDB and Delphix. Expect hands-on posts about installation, day-to-day administration, backup and recovery, performance tuning, replication and upgrades.

Optimizer Statistics Gathering – pending and history

By Franck Pachot . This was initially posted to CERN Database blog on Wednesday, 12 September 2018 where it seems to be lost. Here is a copy thanks to web.archive.org Demo table I create a table for the demo. The CTAS gathers statistics (12c online statistics gathering) with one row and then I insert more rows: 10:33:56 SQL> create table… 

Building a network bonding between 2 cards on Oracle Linux

I recently needed to configure bonding between 2 network cards on a customer side and I wanted trough this blog to share my findings and how I built it showing some traces. I will also do a short comparison of what is possible or not on the ODA. Why should I use bonding? Bonding is a technology which will allow… 

Password rolling change before Oracle 21c

By Franck Pachot . You may have read about Gradual Password Rollover usage from Mouhamadou Diaw and about some internals from Rodrigo Jorge. But it works only on 21c which is only in the cloud, for the moment, in Autonomous Database and DBaaS (but here I’ve encountered some problems apparently because of a bug when using SQL*Net native encryption). But… 

Cluster level encryption for PostgreSQL 14

The discussions how and why TDE (Transparent data encryption) should be implemented in PostgreSQL goes back several years. You can have a look at these two more recent threads to get an idea on how much discussion happened around that feature: [Proposal] Table-level Transparent Data Encryption (TDE) and Key Management Service (KMS) Re: Internal key management system Finally an essentials… 

Running two Patroni on one host using an existing etcd

Have you ever asked yourself, how to create a second Patroni PostgreSQL cluster on an existing server using the existing etcd? My first idea was to study the documentation of Patroni, but unfortunately without big success. This post should help to identify the changes you have to do on the hosts to run two parallel Patroni clusters using an existing… 

SQL Server TCP: Having both Dynamic Ports and Static Port configured

Introduction Have you ever seen an SQL Server instance configured to listen on both “TCP Dynamic Ports” and “TCP (static) Port”? This kind of configuration can be caused by the following scenario: A named instance is installed. By default, it is configured to use dynamic ports. Someone wants to configure the instance to listen to a fixed port and set… 

DynamoDB Scan: the most efficient operation 😉

By Franck Pachot . The title is provocative on purpose because you can read in many places that you should avoid scans, and that Scan operations are less efficient than other operations in DynamoDB. I think that there is a risk, reading those message without understanding what is behind, that people will actually avoid Scans and replace them by something… 

Oracle SPD status on two learning paths

By Franck Pachot . I have written a lot about SQL Plan Directives that appeared in 12c. They were used by default and, because of some side effects at the time of 12cR1 with legacy applications that were parsing too much, they have been disabled by default in 12cR2. Today, there are probably not used enough because of their bad… 

NTP is not working for ODA new deployment (reimage) in version 19.8?

Having recently reimaged and patched several ODA in version 19.8 and 19.9, I could see an issue with NTP. During my troubleshooting I could determine the root cause and find appropriate solution. Through this blog I would like to share my experience with you. Symptom/Analysis ODA version 19.6 or higher is coming with Oracle Linux 7. Since Oracle Linux 7… 

Efficiently query DBA_EXTENTS for FILE_ID / BLOCK_ID

By Franck Pachot . This was initially posted to CERN Database blog on Thursday, 27 September 2018 where it seems to be lost. Here is a copy thanks to web.archive.org Did you ever try to query DBA_EXTENTS on a very large database with LMT tablespaces? I had to, in the past, in order to find which segment a corrupt block… 

Validate your SQL Server infrastructure with dbachecks

Introduction In this blog post, I’ll do an introduction to the PowerShell module dbachecks. dbachecks uses Pester and dbatools to validate your SQL Server infrastructure. With very minimal configuration you can check that your infrastructure is configured following standard best practices or your own policy. We will see the following topics – Prerequisites for dbachecks Installation – Introduction to Pester… 

Oracle write consistency bug and multi-thread de-queuing

By Franck Pachot . This was initially posted on CERN Database blog where it seems to be lost. Here is a copy thanks to web.archive.org Additional notes: – I’ve tested and got the same behaviour in Oracle 21c – you will probably enjoy reading Hatem Mahmoud going further on Write consistency and DML restart Posted by Franck Pachot on Thursday,…