NVMes write back vs. write through performance
Recently I was running some benchmarks to double-check that the performance of AMD EPYCs servers delivered by Company A, match the performance of those delivered by Company B. I was using our benchmark automation tool (about which I may write a bit more in the…
Important behaviour change between bash version 4.3 and 4.4
Please be aware about important behaviour change between bash version 4.3 and 4.4. You can observe it for example while migrating from Oracle Linux 7 to 8/CentOS 7 to Rocky Linux 8/etc. as version 7 of RHEL compatible system comes with bash 4.2, whereas version…
Oracle ACE
After less than 2 years after becoming Oracle ACE Associate, I’m happy to share that I have been promoted to Oracle ACE! I have recently changed my focus from Oracle Database to MySQL, but as it is currently owned by Oracle, I hope I will…
Change is the only constant…
I have a feeling that the name of my blog has never been so true :). Since today I work for Proton Technologies AG (https://protonmail.com, https://protonvpn.com). Still as a database engineer, but with completely different database engine – MySQL! Even though Oracle database is a…
COMMON_USER_CONNECT lockdown profiles feature in Oracle Database 19c
After upgrading some CDBs to 19c, we hit the problem of not being able to connect as common users to the PDBs. In all affected CDBs, lockdown profiles were in place with following definition regarding common user connection part: It worked well in 12c, but…
Smart Sizing of Fast Recovery Area in Cloud Environments
This is just to let you know about my recent article, published in Oraworld magazine. If you want to learn how to size FRA in a smart way, don’t hesitate to have a look – Oraworld Edition #23, December 2020.
PDB_OS_CREDENTIAL and PL/SQL external libraries
In the previous blog post I have described PDB_OS_CREDENTIAL initialization parameter and when it can help you in isolating PDBs from each other. Today I’ll show you an example of how it works with PL/SQL external libraries. Of course we need to setup the whole…
PDB_OS_CREDENTIAL and external jobs
After introduction of Multitenant option, Oracle provided additional ways to ensure proper isolation between pluggable databases. PDB_OS_CREDENTIAL initialization parameter is part of them. It allows to use specified operating system user while interacting with operating system from a PDB. According to documentation, it is taken…
How to generate DDLs of existing lockdown profiles
In my last blog post I mentioned that I’ll write a new one on how to generate DDLs to recreate existing lockdown profiles – the time has come :). When I had to do it for the first time, I thought it would be as…
Lockdown profiles definition – NUL character
Playing more with lockdown profiles, I have discovered another interesting bit. For some entries and some columns of CDB/DBA_LOCKDOWN_PROFILES views (which are based on LOCKDOWN_PROF$ table), there is unnecessary NUL (ASCII code 0) character added at the end. In our environment it was the case…