Oracle

Postgres vs. Oracle access paths II – Index Only Scan

By Franck Pachot . In the previous post I've explained a sequential scan by accident: my query needed only one column which was indexed, and I expected to read the index rather than the table. And(…)

Oracle Cloud: script to stop all PaaS services

By Franck Pachot . With metered cloud services, keeping all your instances running may become expensive. The goal is to start them only when you need them. Here is a script that stops all instances you have on the Oracle(…)

Display Data Guard configuration in SQL Developer

By Franck Pachot . The latest version of SQL Developer, the 17.2 one released after Q2 of 2017, has a new item in the DBA view showing the Data Guard configuration. This is the occasion to show how you can(…)

Postgres vs. Oracle access paths I – Seq Scan

By Franck Pachot . Here is the first test I've done for my Postgres vs. Oracle access paths series and the first query did a sequential scan. It illustrates the first constant you find in the(…)

Postgres vs. Oracle access paths – intro

By Franck Pachot . This is the start of a series on PostgreSQL execution plans, access path, join methods, hints and execution statistics. The approach will compare Postgres and Oracle. It is not a comparison to see which one is(…)

Postgres vs. Oracle access paths VII – Bitmap Index Scan

By Franck Pachot . In the previous post we have seen the Index Scan, where a where clause condition uses the index structure to find rows and then fetches remaining columns from the table. The case(…)

Recommended DB Parameters on the Oracle Database Appliance (ODA)

When creating a DB on the ODA using # oakcli create database -db <db-name> a template is used to set a couple of DB parameters like e.g. _datafile_write_errors_crash_instance=FALSE _db_writer_coalesce_area_size=16777216 _disable_interface_checking=TRUE _ENABLE_NUMA_SUPPORT=FALSE(…)

ODA X6 installation: re-image

By Franck Pachot . The Oracle Database Appliance is shipped with a bare-metal installation which may not be the latest version. You may want to have it virtualized, or get the latest version to avoid further upgrade, or install an(…)

12c Multitenant Internals: VPD for V$ views

By Franck Pachot . I described in an earlier post on AWR views how the dictionary views were using metadata and object links to show information from other containers. But this mechanism cannot work for fixed(…)

12cR2 Application Containers and Foreign Keys

By Franck Pachot . Application Container brings a new way to share data among databases, and adds a new dimension to referential integrity. A foreign key in an application PDB can reference a row belonging to a root data link(…)