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Database

Everything our consultants learn while running databases for customers: Oracle, PostgreSQL, SQL Server, MySQL, MariaDB, MongoDB and Delphix. Expect hands-on posts about installation, day-to-day administration, backup and recovery, performance tuning, replication and upgrades.

Oracle 12c – How to Recover lost DataGuard Broker Configuration Files

By William Sescu If you are using RMAN to back up your database, you are already doing the right thing. However, RMAN does not take care of everything. e.g. it is not backing up the following things, to mention just a few. Oracle Home Grid Infrastructure Home Data Guard broker files Password File SQL*Net file like ldap.ora, sqlnet.ora, tnsnames.ora and… 

Introducing AlwaysOn availability groups on Linux

A couple of days ago, Microsoft has rolled out the SQL Server vNext CTP 1.3 which includes very nice features and the one that interested me in the supportability of AlwaysOn availability groups on Linux. That is definitely a good news because we may benefit from new ways of architecting high-availability. There are a lot of new cool enhancements, which… 

Oracle 12cR2: Online tablespace encryption

By Franck Pachot . By default, all data is visible in the datafiles. Transparent Tablespace Encryption (TDE) can be used to get them encrypted. It requires Enterprise Edition plus Advanced Security Option. Except in the Oracle Cloud when it is available – and mandatory – in all editions. And we can foresee that security policies will be enforced in the… 

12cR2: Recover nonlogged blocks after NOLOGGING in Data Guard

By Franck Pachot . You can accept to do NOLOGGING operations on bulk loads or index build according that you do a backup just after, and that your recovery plan mentions how to load the data again in case of media recovery. With a standby database, we usually force logging because we want redo to be generated for all operations… 

Oracle 12c – Recreating a Controlfile in a Data Guard environment with noresetlogs

By William Sescu Sometimes you might run into situations where the controlfile does not represent the backups and archivelogs correctly, because of a mismatch of the control_file_record_keep_time and the RMAN retention. The controlfile has non circular and a circular records. Non circular are e.g. database information, redo threads, datafiles and so on. These non circular records don’t age out, however,… 

12c Unified Auditing and AUDIT_TRAIL=DB in mixed mode

By Franck Pachot . Oracle enables some auditing by default, and if you don’t do anything, the tables where it is stored will grow in SYSAUX. Don’t wait to get an alert when it is too late. Everything that fills something automatically must be managed to archive or purge automatically. If not, one day you will have a problem. Imagine… 

BLOG Technoark 2017 Conference – Blockchain, beyond the bitcoin.

BLOG Technoark 2017 Conference – Blockchain, beyond the bitcoin. and How applying Blockchain for Enterprise security and data management. I post a brief personal impression of the TechnoArk Conference 2017 in TechnoArk center of Sierre /Switzerland) This TechnoArk Center is based on three essentials parts: • The Ark Accelerator leverages new technologies and guides them to a commercial application. It is… 

12cR2: lockdown profiles and ORA-01219

By Franck Pachot . When you cannot open a database, you will get some users unhappy. When you cannot open multitenant database, then the number of unhappy users is multiplied by the number of PDBs. I like to encounter problems in my lab before seeing them in production. Here is a case where I’ve lost a file. I don’t care… 

Dataguard Oracle 12.2: Keeping Physical Standby Sessions Connected During Role Transition

By Mouhamadou Diaw As of Oracle Database 12c Release 2 (12.2.0.1), when a physical standby database is converted into a primary you have the option to keep any sessions connected to the physical standby, without disruption, during the switchover/failover. When the database is reopened as the primary, the suspended sessions resume their operations as if nothing had happened. If the… 

Converting a column from one data type to another in PostgreSQL

Last week at a customer the following question came up: We have a varchar2 column in Oracle that contains a date but actually is stored as a string. When we want to convert this column to be a real date data type in Oracle we can use dbms_redefinition. How can we do that in PostgreSQL? The first answer that came…