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Petre Radut

When you change the UNDO_RETENTION parameter, the LOB segment’s retention value is not modified

By | Database Administration & Monitoring, Database management, Development & Performance, Hardware & Storage, Oracle | No Comments

Below, I will try to explain, a particular case for the general error : ORA-01555 snapshot too old error.. Normally, when we have this error, we are trying to adapt the retention parameters or to tune our queries. SQL> show parameter undo; NAME TYPE VALUE ———————————— ———– —————————— temp_undo_enabled boolean FALSE undo_management string AUTO undo_retention integer 3600 –extended from 900, undo_tablespace string UNDOTBS1 But, are some scenarios where the above rule is not working . We…

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Petre Radut

Create a primary database using the backup of a standby database on 12cR2

By | Database Administration & Monitoring, Database management, Oracle | No Comments

The scope of this blog will be to show how to create a primary role database based on a backup of a standby database on 12cR2. Step1: We are assuming that an auxiliary instance has been created and started in nomount mode. rman target / restore primary controlfile from ‘backup_location_directory/control_.bkp’; exit; By specifying “restore primary” , will modify the flag into the controlfile, and will mount a primary role instance instead of a standby one….

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Petre Radut

Recover a corrupted datafile in your DataGuard environment 11G/12C.

By | Database Administration & Monitoring, Database management, Development & Performance, Oracle | No Comments

On a DG environment, a datafile needs to be recovered on the STANDBY site, in two situations : when is deleted or corrupted. Below, I will explain  how to recover a corrupted datafile, in order to be able to repair the Standby database, without to be necessary to restore entire database. Initial situation : DGMGRL> connect / Connected to “PROD_SITE2” Connected as SYSDG. DGMGRL> show configuration; Configuration – CONFIG1 Protection Mode: MaxPerformance Members: PROD_SITE2 -…

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David Barbarin

Azure SQL Managed instances, Business Critical Tier and high availability

By | Cloud, SQL Server | No Comments

Last blog of this year 2018 with SQL databases and Cloud Azure and this is not trivial choice. <Speculation mode> I would say year 2019 could be important for all stakeholders. Cloud transformation has begun in many forms at customer shops and we heard about some big actors who are coming in Switzerland including Azure or Google. Data Platforms services will not be an exception in some degree of magnitude … <end of speculation mode>….

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David Barbarin

SQL Server 2019 availability groups – Introduction to R/W redirection

By | Database Administration & Monitoring, Database management, SQL Server | 3 Comments

writeThis is a second write-up about SQL Server 2019 CTP2.0 and availability group new features. This time the interesting one is about READRWRITE redirection capabilities. A couple of months ago, I wrote about SQL Server 2017 and new read-scale capabilities and listener management challenges regarding the operating system. Indeed, there are some scenarios where including listener will not as easy as we did with common ones on the top of Windows operation system. A list of…

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Grégory Steulet

Oracle Open World 2018 D3: Replication what’s new in MySQL 8

By | Database Administration & Monitoring | No Comments

For this last day (25.10.2018) at Oracle Open World my first technical session was “Replication what’s new in MySQL 8“. This session was given by Nuno Carvalho – Oracle MySQL Principal Software Engineer, Vitor Oliveira – Oracle MySQL Performance Architect, Louis Soares – Oracle MySQL Software Development Director. You can find the list of new features linked with MySQL InnoDB Cluster here. They introduced the session with the challenges a database has to face today: We…

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David Barbarin

SQL Server availability groups, SQL Browser and Shared Memory considerations

By | Database Administration & Monitoring, SQL Server | One Comment

Few weeks ago, my colleagues and me discussed availability groups and network considerations for one of our customers including disabling SQL Browser service and shared memory protocol. The point was disabling both features may lead to unexpected behaviors when creating availability groups. Let’s start with the SQL Browser service. It is not uncommon to disable this service at customer shops and to use directly SQL Server listen ports instead. But if you go trough the…

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Petre Radut

How to migrate Grid Infrastructure from release 12c to release 18c

By | Application integration & Middleware, Database Administration & Monitoring, Database management, Oracle | No Comments

Oracle Clusterware 18c builds on this innovative technology by further enhancing support for larger multi-cluster environments and improving the overall ease of use. Oracle Clusterware is leveraged in the cloud in order to provide enterprise-class resiliency where required and dynamic as well as online allocation of compute resources where needed, when needed. Oracle Grid Infrastructure provides the necessary components to manage high availability (HA) for any business critical application. HA in consolidated environments is no…

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David Barbarin

First steps into SQL Server 2019 availability groups on K8s

By | Cloud, Database management, DevOps, SQL Server | No Comments

A couple of weeks ago, Microsoft announced the first public CTP version of next SQL Server version (CTP2). It is not a surprise, the SQL Server vNext becomes SQL Server 2019 and there are a plenty of enhancements as well as new features to discover. But for now, let’s start with likely one of my favorites: availability groups on Kurbernetes (aka K8s). As far I may see from customers and hear from my colleagues as well,…

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