By Franck Pachot . I’ve described Oracle 12c metadata and object links internals in a previous post. But before that, the first time I investigated on it, I made a wrong assumption because I was looking at AUDIT_ACTIONS which is not correctly implemented. That investigation came from a question on dba-village. And recently Ivica Arsov (@IvicaArsov) has made an interesting…
By Franck Pachot . I’ll present here 3 ways to run a query for each result of another query. Let’s take an exemple: get all executions plan (select from dbms_xplan.display_cursor) for each of my queries (identified from v$sql). The 90’s way was to run the first query, which generates the second queries into a spool file, and execute that file.…
By Franck Pachot . If we don’t mind about loosing our changes, then can we disable logging for DML? This is a question I’ve heard a lot. Ok, you don’t need to recover your changes but Oracle may want to recover the consistency of its datafiles anyway. And that’s why datafiles blocks changed though the buffer cache always generate redo.…
By Franck Pachot . How to migrate from non-CDB to CDB? Of course all known migration methods works. But there is also another solution: upgrade to 12c if necessary and then convert the non-CDB to a PDB. This is done with the noncdb_to_pdb.sql which converts a non-CDB dictionary to a PDB one, with metadata and object links. But do you…
By Franck Pachot . During our Oracle 12c New Features workshop I had a very good question about whether the session statistics are reset or not when doing ALTER SESSION SET CONTAINER. My initial thought was that they were not reset because it’s the same session (same SID and SERIAL#). But when I’m not 100% sure about something, I test…
By Franck Pachot . 12c came with a very nice feature: privilege analysis. You don’t know which privileges are required? then just grant DBA, run your application, and check which minimal privileges are needed. And today, I’ve discovered how it is very powerful: you can even see privileges used internally, even when not done by SQL, and even not documented.…
By Franck Pachot . SQL plan Directives have been introduced in 12c. If you have scripts that check their states (and I have that as I prefer to monitor closely the features that are new) you probably have seen a difference when going from 12.1.0.1 – the first release of 12c and the only one avilable yet in Standard Edition…
In one of my last blog, named: “Oracle Audit Vault and Database Firewall (AVDF) 12.1 – installation on VirtualBox” I explained how to install AVDF on VirtualBox. Since some of you asked for a blog on “How to configure AVDF”, I decided to write this posting on AVDF post-installation configuration. This one only concerns the post-installation phase, a third blog…
By Franck Pachot . I’ve blogged about multitenant internals at the time when 12.1.0.1 was just released. Something has changed in 12.1.0.2 and blogging about it was in my todo list for a long time. Now the occasion to do it has been triggered by a question on Oracle Forums about CDB_DATA_FILES not showing PDB$SEED datafiles because there is an…
Making errors is human and when you configure a new Oracle Grid Infrastructure environment (especially one with a large number of nodes), mistakes can happen when configuring ASMLIB on all nodes. If you get an error looking like”PRVG-10122 : ASMLib configuration…does not match with cluster nodes”, there is a simple solution to fix it. When you are installing Grid Infrastructure,…
By Franck Pachot . Do you know why Oracle Database is a leader in the database market since 30 years? Do you know any other software that is still the leading solution after decades? I think that it is because Oracle has been a good software from the get-go. Many early decisions in the software architecture have revealed themselves later…
By Franck Pachot . I have recently published a script to check index fragmentation. But then, do you COALESCE or REBUILD? Well, there also is another option: ALTER INDEX SHRINK SPACE. Let’s compare all those index defragmentation operations. Fragmented index I have an index created when the table had 1 million rows. Then, I deleted 90% of the rows. Here…
