Database management

RESULT_CACHE hint expiration options

By Franck Pachot . The result cache is very nice when base tables are static: get the result without any buffer get, without any join or sorts. But as soon as any DML occurs on one of the tables(…)

Multitenant vs. schema based consolidation

By Franck Pachot . If you want to install multiple instances of a software, for example you host the ERP for several companies or subsidiaries, you have 3 solutions: have one database and multiple schema have multiple databases have(…)

Oracle Log Writer and Write-Ahead-Logging

By Franck Pachot . I posted a tweet with a link to a very old document – 20 years old – about ‘internals of recovery’. It’s a gem. All the complexity of the ACID mecanisms of Oracle are(…)

Oracle Database Cloud Service – My first trial

By Franck Pachot . The cloud has been annouced, I want to try. From the cloud.oracle.com/database website, there is Trial only for the ‘Database Schema Service’ so I asked fot it, received an e-mail with connection info and it(…)

RAC buffer states: XCUR, SCUR, PI, CI

By Franck Pachot . In RAC, blocks are copied across instances by the Global Cache Service. In single instance, we have only two status: CR for consistent read clones where undo is applied, and CUR for the current version(…)

Multithreaded 12c and ‘connect / as sysdba’

By Franck Pachot . In Oracle 12c you can run Oracle processes as operating system threads, lowering the number of OS processes. But you can’t use OS authentification: you need to provide a password. Here is a way to(…)

Buffer pool advisory in AWR

By Franck Pachot . In Oracle memory advisors: how relevant ? I said that advisors are calculating their recommendations from statistics cumulated since the begining of the instance, even in AWR which is supposed to cover only a(…)

Does the block size matter?

By Franck Pachot . The default block size is 8k in Oracle. This is the most common. Sometimes, people create the database with 16k block size for datawarehouses. You can also find some 32k block size, but less common(…)

SQL Server 2016 CTP2: Stretch database feature – Part 2

In my previous blog SQL Server 2016 CTP2: Stretch database feature – Part 1, I explained how to prepare your instance and your database to enable the Stretch feature for your table. Now I present you how to enable(…)

statistics_level parameter

With Enterprise Manager Cloud Control 12c configuring and using the compliance standard utility allows us to discover events we should not have seen in other ways. Today at a customer’s site I discovered the following message:   The configuration(…)