By Franck Pachot . In 12.1.0.1 the common user prefix was set to C## by an underscore parameter. In 12.1.0.2 it’s a documented parameter and you can change it. But is there any reason for that? I can think of a reason. Let’s say I want to use external authentication for my common users SQL> show parameter prefix NAME…
By Franck Pachot . Here is a long answer for a question on our forum about online move: what is internal mechanism to store/keep ongoing changes in that particular datafile while copying is in progress. The short answer is that there is absolutely no lock, just small synchronization and messaging between sessions. And a very small overhead while the move…
Available methods to enable 10046 trace are described in My Oracle Support Note 376442.1. You can enable 10046-tracing – on session level (alter session) – for other sessions (e.g. with oradebug, the package DBMS_MONITOR or DBMS_SYSTEM) What is not covered with the methods above is the possibility to trace a specific SQL-statement, which runs “somewhen” in the future on the…
By Franck Pachot . 12c SQL Plan Directives, a side effect, a bad application design, a bug… and the occasion to show how to quickly troubleshoot. An application has long response time since 12c migration. No blind guesses, no reason to compare with previous version, let’s just troubleshoot performance with methodical approach. Time Model You should already know that, I…
By Franck Pachot . Yesterday I was giving my ‘Interpreting AWR Reports’ Prezi at Oracle Midlands. There is a point where I explain that I always check the ‘Captured SQL account for …% of Total DB Time (s)’ in order to know whether I’ll get all details in the report or not. There are two main reasons why the most…
By Franck Pachot . In the previous post I’ve explained how to use ‘snapshot copy’ PDB creation for thin provisioning and quick restore of initial state for continuous integration tests. If you don’t have the multitenant option, you need a remote CDB to do it. Here is a way to do the same on only one single-tenant CDB. The idea…
By Franck Pachot . How do you manage your continuous integration tests on the database? You need to restart at the same state for probably a hundred of tests. Recreating the schema and test data takes too long. Oracle is not optimized for DDL. Restoring the database takes too long. Even if you data is small, there is those SYSTEM,…
By Franck Pachot . In multitenant a session can switch from one container to another. There are a few restrictions such as a transaction cannot span multiple containers. But how do sessions parameters behave? It seems that there is a small inconsistency. I was looking at some adaptive plan and SPM behavior (see this tweeter conversation) and played with the…
By Franck Pachot . I use transportable tablespaces a lot since 8i, here are just a few examples. Same disclaimer here as in the first post of the series: don’t expect to get those posts close to what you will have at the exam, but they cover important points that matches the exam topics. Documentation Information about the exam says:…
By Franck Pachot . Yesterday I came upon a comment on oracle-l while I was reading my slides for the UKOUG TECH15 SuperSunday. I’ve one slide and one demo about disabling SPD usage but that’s not enough to explain all variations of what ‘usage’ means here. The comment on Oracle-L was: Seems like even after disabling sql plan directives they…
By Franck Pachot . Let’s see the different ways to create a PDB, with different tools. Same disclaimer here as in the first post of the series: don’t expect to get those posts close to what you will have at the exam, but they cover important points that matches the exam topics. Documentation Information about the exam says: Be prepared…
By Franck Pachot . This post starts a series about things I wrote while preparing the OCM 12c upgrade exam. Everything in those posts are written before taking the exam – so don’t expect any clue about the exam here. It’s based only on the exam topics, and only those points I wanted to brush up, so don’t expect it…
