Infrastructure at your Service

All posts by Mouhamadou Diaw

Mouhamadou Diaw
Consultant

Mouhamadou Diaw has more than ten years of experience in IT domains. He is specialized in Oracle technologies (engineered system, architecture, backup and recovery, high availability, security, audit etc.). Mouhamadou Diaw is Oracle professional Certified (8i, 10g, 11g, 12c), Oracle RAC 11gR2 Certified Expert , Oracle Database 11g Security Certified and CISA (Isaca). He received a Doctorate in Heat and Humidity Transfer of INSA Toulouse, France. His branch-related experience covers Insurance, Retail, International Organizations, Transport & Logistics, etc.
Mouhamadou Diaw

Migrating from oracle to postgresql with ora2pg

By | Database Administration & Monitoring | 5 Comments

PostgreSQL is one of the most used Rdbms. In this blog we are going to talk about migrating from oracle to postgresql using ora2pg. A previous blog about this topic can be found here. After installing ora2pg tool, we will see how to configure and to run it to migrate our data. We are using an oracle 12.1 database and a postgresql 9.6.2. The server is runing on OEL 7.2 The oracle database and the…

 
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Mouhamadou Diaw

Sharding with Oracle 12c R2 Part II : Scalability and Connections

By | Database Administration & Monitoring | No Comments

In previous blog, we talked about system-managed sharding. We saw how it is possible to create shard databases with Oracle 12c R2. Below we remind the configuration we used. VM sharddemo1: catalog VM sharddemo2: shard VM sharddemo3: shard One of the characteristics of sharding is the scalability, and in this blog we are going to add a new shard on a new server. The new configuration will be like below VM sharddemo1: catalog VM sharddemo2:…

 
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Mouhamadou Diaw

Is your DBA_FEATURE_USAGE_STATISTICS up-to-date?

By | Database Administration & Monitoring | One Comment

Last day we were doing a licensing review for a client. As many dbas may already know, this require to execute some oracle scripts at OS level and database level. Among these scripts we have the script options_packs_usage_statistics.sql (docId 1317265.1) which is an official oracle script to check the usage of separately licensed Oracle Database Options/Management Packs This script is using the DBA_FEATURE_USAGE_STATISTICS table to retrieve info. And sometimes it may happen that data of…

 
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Mouhamadou Diaw

Sharding with Oracle 12c R2 Part I

By | Database Administration & Monitoring | 12 Comments

Oracle 12.2 comes with many new features. In this article we are going to talk about sharding. It is a database scaling technique based on horizontal partitioning of data across multiple oracle databases called sharded databases (SDB). Each shard contains the table with the same columns but a different subset of rows. Sharding can be represented like this For DBA: SDB is in fact multiples databases that can be managed collectively or individually There are…

 
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Mouhamadou Diaw

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

By | Database Administration & Monitoring | One Comment

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 database (or an individual PDB) is not opened in the primary role, the sessions will be terminated. To…

 
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Mouhamadou Diaw

Database Diagram using SQL Developer

By | Database Administration & Monitoring | No Comments

Last Day a client asked me if I can generate a relational diagram for an oracle schema. He was just preparing a migration and wanted to see how tables are organized in the schema. In this article we will show how this is possible with SQL Developer . We are using SQL Developper 4.1.3.20 Once SQL Developer started just proceed as following : Launch File ==>Data Modeler ==>Import==>Data Dictionary Choose your connection and Click Next…

 
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Mouhamadou Diaw

Temporal tables with PostgreSQL

By | Database Administration & Monitoring | No Comments

In this blog we are going to talk about a nice extension in PostgreSQL: temporal_tables. This extension provides support for temporal tables. What is a temporal table? Just a table that tracks the period of validity of a row. When implemented, this feature allows you to specify that old rows are archived into another table (that is called the history table). This can be useful for many purposes -Audit -Comparison -Checking table state in the…

 
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Mouhamadou Diaw

Dataguard Oracle 12.2 : Support for Multiple Observers

By | Database Administration & Monitoring | One Comment

With Oracle 12cR2 it is now possible to configure multiple observers within a single Oracle Data Guard broker configuration. Multiple observers provide an immediate benefit for High Availability. If one observer fails, there are additional observers that can continue to monitor the status of the configuration. In this blog we are going to talk about this new feature. Our configuration have 3 servers: primaserver.localdomain with db_unique_name ORCL_SITE standserver1.localdomain with db_unique_name ORCL_SITE1 standserver2.localdomain with db_unique_name ORCL_SITE2…

 
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Mouhamadou Diaw

Dataguard Oracle 12.2 : Support for Multiple Automatic Failover Targets

By | Database Administration & Monitoring | No Comments

In a previous blog, we talked about Fast-Start Failover with the MaxProtection mode. With Oracle 12.2 Oracle Data Guard now supports multiple failover targets in a fast-start failover configuration. Previous functionality allowed for only a single fast-start failover target. If the failover target was unable to meet the requirements for fast-start failover at the time of primary failure, then an automatic failure would not occur. Designating multiple failover targets significantly improves the likelihood that there…

 
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Mouhamadou Diaw

Dataguard Oracle 12.2 : Fast-Start Failover with Maximum Protection

By | Database Administration & Monitoring | No Comments

With Oracle 12.1 the one requirement to configure Fast-start Failover is to ensure the broker configuration is operating in either Maximum Availability mode or Maximum Performance mode. With 12.2 Fast-Start Failover can be now configured with the Maximum Protection Below our broker configuration DGMGRL> show configuration; Configuration – ORCL_DR Protection Mode: MaxPerformance Members: ORCL_SITE – Primary database ORCL_SITE1 – Physical standby database ORCL_SITE2 – Physical standby database Fast-Start Failover: DISABLED Configuration Status: SUCCESS (status updated…

 
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