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dbi services BLOG

Welcome to the dbi services Blog! This IT blog focuses on database, middleware, and OS technologies such as Oracle, Microsoft SQL Server & SharePoint, EMC Documentum, MySQL, PostgreSQL, Sybase, Unix/Linux, etc. The dbi services blog represents the view of our consultants, not necessarily that of dbi services. Feel free to comment on our blog postings.

Franck Pachot

12cR2 DML monitoring and Statistics Advisor

By | Database management | No Comments
 

 Monitoring DML to get an idea of the activity on our tables is not new. The number of insert/delete/update/truncate since last stats gathering is tracked automatically. The statistics gathering job use it to list and prioritize tables that need fresh statistics. This is for slow changes on tables. In 12.2 we have the statistics advisor that goes further, with a rule that detects volatile tables: SQL> select * from V$STATS_ADVISOR_RULES where rule_id=14;   RULE_ID NAME…

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William Sescu

OUD – Oracle Unified Directory 11.1.2.3, Oracle generates more and more LDAP lookups with every release

By | Database Administration & Monitoring | No Comments
 

 After installing OUD some time ago, I was doing some tests to see how it performs, and as long as I do ldap searching on the command line it looks very good. I am running Unified Directory 11.1.2.3.170117 (latest PSU), just for the protocol and I use the OUD only for TNS resolving and nothing else. However, Oracle clients are not connecting with “ldapsearch”, they are using “sqlplus” and the TNS name is resolved automatically…

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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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William Sescu

OUD – Oracle Unified Directory 11.1.2.3 Tuning, It is not always the servers fault

By | Database Administration & Monitoring | No Comments
 

 The default configuration which is shipped with OUD is not meant to be ready for enterprise usage. The default settings of OUD are targeted at evaluators and developers who run equipment with limited resources, and so it is quite likely that you run into performance issues if you don’t change anything, before going into production. The OUD performance depends on a lot of things like Network configuration/routing/firewalls/bonding OUD version and configuration (Replication, TLS) Java version…

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Daniel Westermann

Can I do it with PostgreSQL? – 14 – optimizer hints

By | Database Administration & Monitoring | No Comments
 

 This is a question that comes up quite often: How can I use optimizer hints in PostgreSQL as I can do it in Oracle? Well, you cant, and the reasons are this: Poor application code maintainability: hints in queries require massive refactoring. Interference with upgrades: today’s helpful hints become anti-performance after an upgrade. Encouraging bad DBA habits slap a hint on instead of figuring out the real issue. Does not scale with data size: the…

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Franck Pachot

12cR2 DBCA, Automatic Memory Management, and -databaseType

By | Database Administration & Monitoring, Database management | One Comment
 

 This post explains the following error encountered when creating a 12.2 database with DBCA: [DBT-11211] The Automatic Memory Management option is not allowed when the total physical memory is greater than 4GB. or when creating the database directly with the installer: [INS-35178]The Automatic Memory Management option is not allowed when the total physical memory is greater than 4GB. If you used Automatic Memory Management (AMM) you will have to think differently and size the SGA…

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Franck Pachot

When automatic reoptimization plan is less efficient

By | Database Administration & Monitoring | 3 Comments
 

 11gR2 started to have the optimizer react at execution time when a misestimate is encountered. Then the next executions are re-optimized with more accurate estimation, derived from the execution statistics. This was called cardinality feedback. Unfortunately, in rare cases we had a fast execution plan with bad estimations, and better estimations lead to worse execution plan. This is rare, but even when 9999 queries are faster, the one that takes too long will gives a…

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Daniel Westermann

Can I do it with PostgreSQL? – 13 – create database

By | Database Administration & Monitoring | No Comments
 

 Following the last post about which tools you can use to create your PostgreSQL instance in this post we’ll look at how you can do the “create database” part that you would do in Oracle when not using the database configuration assistant. Of course can can create a database in PostgreSQL but it is not the same as it is in Oracle. To actually create your Oracle database you would do something like this once…

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Morgan Patou

Documentum – Increase the number of concurrent_sessions

By | Entreprise content management | No Comments
 

 In Documentum, there is a parameter named concurrent_sessions which basically defines how many sessions a Content Server can open simultaneously. This parameter is defined in the server.ini file (or server_<dm_server_config.object_name>.ini on a Remote Content Server) of each docbase and it has a default value of 100. An empty Content Server with an IndexAgent and D2 installed (without user using it) will usually take around 10 sessions for the jobs, for the searches, aso… As soon…

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Morgan Patou

Documentum – Wrong dfc versions after installation, upgrade or patch

By | Entreprise content management | No Comments
 

 If you are familiar with Documentum or if you already read some of my blogs, then you probably already know that EMC has sometimes issues with libraries. In a previous blog (this one), I talked about the Lockbox versions which caused us an issue and in this blog, I will talk about DFC versions. Whenever you install a CS patch or another patch, it will probably have its own DFC libraries simply because EMC fixed something…

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Morgan Patou

Documentum – Thumbnail not working with TCS

By | Entreprise content management | No Comments
 

 A few months ago and right after a migration of around 0.5TB of documents, we enabled the TCS for one of our Application. We were using a Content Server 7.2 P05 with the associated D2 4.5 P03. As already mentioned in a previous blog, D2 4.5 doesn’t handle the previews of the documents and therefore there were also a Thumbnail Server used by this Application. The setup of the TCS for the document filestores went…

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Daniel Westermann

Can I do it with PostgreSQL? – 12 – dbca (database configuration assistant)

By | Database Administration & Monitoring | No Comments
 

 Short answer: No. Long answer: No. Every other possible answer: No. There is no such tool in PostgreSQL. In Oracle you can use the database configuration assistant to create your Oracle database. But this is not a must, you can do the same using scripts. Either you use dbca to generate scripts based on the questions you answered in the several screens or you use your own set of scripts to create an Oracle database…

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