Infrastructure at your Service

All posts by Franck Pachot

Franck Pachot
Technology Leader
Principal Consultant

OCM 12cFranck Pachot has 20 years of experience in Oracle databases. Through his expertise as a DBA, Oracle expert, data architect, and performance specialist, he is able to cover all database areas: architecture, data modeling, database design, tuning, operation, and training. Franck knows how to enable an efficient collaboration between the developers and the operational team when it comes to troubleshooting issues or performance tuning.

RSSOracle ACEOracle ACE Franck is Oracle Certified Master (OCM 12c), Oracle ACE Director and proud member of Oraworld-team and Oak Table.

POUG
Cracow (PL), Sept. 1st

12cR2 Statistics Advisor: Do you gather statistics in the way the optimizer expects them?
SOUG
Swiss Oracle User Group

Leman: Calculer les statistiques comme prévu par l'optimiseur
Baden: Single-Tenant 12.2
OOW17
San Francisco, Oct 1st

Multitenant: Trust It by Understanding Beyond What Is Documented
DOAG2017
Nürnberg, Nov, 21st

Multitenant internals
UKOUG TECH17
From Transportable Tablespace to Pluggable Databases
Join Methods: Nested Loop, Hash, Sort, Merge, Adaptive


Franck Pachot

#UKOUG_TECH17

By | Oracle | No Comments

Award I’ve received an award for an article I’ve written last year, the Most Read Oracle Scene Article in 2016 – Technology. I like to write for Oracle Scene magazine. It is rare today to have a magazine both available in a paper version, and also publicly available on the web. And I must say that as an author, all the people behind are doing a great work. Thanks to them and thanks for the…

 
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Franck Pachot

12c Multitenant Internals: compiling system package from PDB

By | Oracle | No Comments

When I explain the multitenant internals, I show that all metadata about system procedures and packages are stored only in CDB$ROOT and are accessed from the PDBs through metadata links. I take an example with DBMS_SYSTEM that has nothing in SOURCE$ of the PDB. But I show that we can compile it from the PDB. This is my way to prove that the session can access the system objects, internally switching the session to the…

 
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Franck Pachot

Unstructured vs. structured

By | Oracle | One Comment

The title of this blog post was: “Tracing DBMS_RCVMAN for reclaimable archivelogs” until I started to write the conclusion… In a previous post I mentioned that there’s a bug with archivelog deletion policy when you want to mention both the ‘BACKED UP … TIMES TO …’ and ‘APPLIED’ or ‘SHIPPED’ as conditions for archived logs to be reclaimable. I opened a SR, they didn’t even try to reproduce it (and I can guarantee you can…

 
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Franck Pachot

Dynamic Sampling vs. Extended Statistics

By | Oracle | 2 Comments

On datawarehouse databases, I frequently recommend increasing the level of dynamic sampling because: Queries have complex predicates with AND, OR, IN(), ranges and correlated values for which the optimizer cannot estimate the cardinality properly Queries are long anyway (compared to OLTP) and can afford more parse time to get an optimized execution plan However, there’s a drawback with this approach because sometimes the dynamic sampling estimation may give bad estimations, and supersedes the static statistics…

 
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Franck Pachot

Multitenant internals: INT$ and INT$INT$ views

By | Oracle | No Comments

This month, I’ll talk – with lot of demos – about multitenant internals at DOAG conference. The multitenant dictionary architecture starts with a simple idea: system metadata and data are in CDB$ROOT and user metadata and data are in PDB. And it could have been that simple. When a session connected to a PDB needs to read some system information, the session context is switched to the CDB$ROOT container and reads from CDB$ROOT SYS tablespace…

 
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