Oracle

DOAG 2017: Automation in progress

A week ago, I had the chance to be speaker at the DOAG Konferenz 2017 in Nürnberg. It’s sometimes hard to find time to be at the conferences because the end of year is quite busy at customers.

Transfer redo in async-mode to the Gold/Master copy of the Production DB for ACFS snapshots

If you store your databases on the cluster filesystem ACFS you may use the provided Perl-script gDBClone from OTN to clone databases or create snapshot databases. It is an interesting approach to create clones from the Production DB(…)

impdp logtime=all metrics=y and 12cR2 parallel metadata

By Franck Pachot . A quick post to show why you should always use LOGTIME=ALL METRICS=Y when using Data Pump. Just look at an example showing the timestamp in front of each line and a message about each task completed(…)

#DOAG2017

By Franck Pachot .

DOAG 2017: avg_row_len with virtual columns

At the DOAG I attended a session “Top-level DB design for Big Data in ATLAS Experiment at CERN” provided by Gancho Dimitrov. The presentation was actually very interesting. As part of Gancho’s improvement activities to reduce space in a table(…)

12c Multitenant Internals: compiling system package from PDB

By Franck Pachot . 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(…)

Unstructured vs. structured

By Franck Pachot . 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(…)

CBO, FIRST_ROWS and VIEW misestimate

By Franck Pachot . There are several bugs with the optimizer in FIRST_ROWS mode. Here is one I encountered during a 10.2.0.4 to 12.2.0.1 migration when a view had an 'order by' in its definition.

Dynamic Sampling vs. Extended Statistics

By Franck Pachot . 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(…)

Automate OVM deployment for a production ready Oracle RAC 12.2 architecture – (part 01)

After having worked with OVM on various architectures I can say that it is a good technology to easily build virtualized environments for production applications. Because it is based on XEN and has simple ways to deal with existing storage(…)