Clemens' Blogs

Kategorie: Oracle

  • Oracle: A possible method to address a slow query if there is time pressure

    Sometimes there is no time for a long analysis of a slow query and a fix (workaround) has to be provided asap. In such cases it often helps to check if a query did run faster with a previous OPTIMIZER_FEATURES_ENABLE-setting. If that is the case, then you also want to find out which optimizer bug…

  • odacli create-appliance failed on an ODA HA

    I recently had to install an Oracle Database Appliance X11 HA and it failed when creating the appliance: It happened randomly in the past that we got this error „host key verification failed“ and we just had to rerun our „odacli create-appliance“ command again. However, this time restarting was not possible: Following MOS Note „ODA…

  • Migrating an Oracle database to another server

    There are several situations when you have to migrate your Oracle databases to a new server. This could be due to hardware lifecycle reasons for on-prem systems or you need to upgrade your Operating System (OS) from Enterprise Linux 8 to Enterprise Linux 9. In this blog I wanted to talk about my recommended methods…

  • Oracle Database on Apple Silicon with Virtualbox 7.1

    I blogged in the past about running an Oracle database for testing purposes on Apple Silicon. Initially with emulated Intel code here and then (when Oracle released its 19c database software for ARM) with UTM as a wrapper for the QEMU hypervisor here. In the meantime another possibility came up since Oracle released its type…

  • What is the fastest method to connect to an Oracle database?

    There are still applications around, which do connect to the database, do some stuff and then disconnect again. I.e. for each and every operation a logon to the database is necessary. This produces unnecessary overhead and is expressed in a high percentage of DB time taken by „connection management call elapsed time“ in the Oracle…

  • Oracle Database Appliance (ODA): Some listeners do not start anymore when booting

    A colleague of mine had the issue some time ago and I recently experienced the same behaviour at a customer’s ODA: A couple of Listeners did not start when booting. Starting them as user grid with worked without any problem though. So what is the issue? Analysis Looking at the listeners which do not start…

  • Running an Oracle Database 19c on Apple Silicon (Apple Macbook Air M1)

    By end of June 2023 Oracle announced the availability of Oracle 19c for the Arm-architecture (aarch64). Consultants and DBAs, who do use a Mac Laptop with Apple Silicon (M1 or M2), have waited quite a long time to run an Oracle database in a Sandbox environment on their Apple machine. The database software Oracle 19c…

  • Building a transportable Oracle Sandbox environment for an Apple Silicon Laptop (MacBook with M1- or M2-processor)

    Since Apple released their Apple Silicon Laptops based on the ARM processor architecture, it became difficult for Consultants with such a device to run their Oracle Sandbox environment, because the main Oracle products are running on the Intel architecture. Hence a virtual machine on an Apple Silicon MacBook cannot be used for e.g. an Oracle…

  • Installing Oracle 23c Free developer release on Proxmox

    Oracle provides an OVA (Open Virtual Appliance) file to install the 23c Free Developer Release on Virtualbox. An OVA file contains metadata and file elements in the Open Virtual Format (OVF) to package and distribute one or more virtual machines. The OVA-file provided by Oracle can also be used to import the Oracle 23c Free…

  • Patching ODA to 19.18.: Error in sshd_config

    I recently patched an Oracle Database Appliance (ODA) from 19.16. to 19.18. Detailed steps on how to patch to 19.18. are available here. During the update-server step I got the following error: So obviously something is wrong with sshd_config. If an error happens when running a job on the ODA with odacli then I check…