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Database Administration & Monitoring

Franck Pachot

DataGuard broker properties – Part I: imported parameters

By | Database Administration & Monitoring, Oracle | One Comment

By Franck Pachot . When you are using the DataGuard Broker, you should always use the broker (with DGMGRL or OEM) to change the parameters that are managed, rather than changing them with ALTER SYSTEM. But do you know which parameters are concerned? I’ve divided the parameters in two parts. All are set by the broker, but only some of them are read when you add a new database to the configuration.

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Daniel Westermann

Connecting your PostgreSQL instance to an Oracle database – The PostgreSQL 9.5 way

By | Database Administration & Monitoring | 8 Comments

As you might know PostgreSQL 9.5 is currently in alpha 2. One of the new features will be the possibility to import foreign schemas. Having this it is no longer required to create all the foreign tables which saves a lot of work. Setting up oracle_fdw was done in exactly the same way as in the previous post. Make sure you use the latest version of oracle_fdw as some internals changed in PostgreSQL 9.5 which…

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Grégory Steulet

MySQL FATAL: error 1040: Too many connections & 1135 Can’t create a new thread

By | Database Administration & Monitoring | No Comments

Hi folks, Some of you probably already got error 1040 by playing with sysbench for instance and multiplying the number of MySQL threads. Documentation and blogs usually simply state that you have to increase the number of max_connections and the open files limit. If you tried and you didn’t succeed this blog is for you. Despite the following entries in /etc/my.cnf the max_connections and open_files_limit are not set correctly: max_connections = 8000 open_files_limit = 8192…

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Daniel Westermann

Connecting your PostgreSQL instance to an Oracle database

By | Database Administration & Monitoring | 16 Comments

For integrating data from other systems PostgreSQL has the concept of foreign data wrappers. Many of these exist for different types of systems. In this post I’ll look into how you may connect PostgreSQL to Oracle. The home of the foreign data wrapper for Oracle (as most of the PostgreSQL stuff) is on github. If you do not want to clone the git repository you can download it from the PostgreSQL extension network, too. For…

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Daniel Westermann

ACFS 12.1.0.2 on Oracle Linux 7.1

By | Database Administration & Monitoring | 2 Comments

Recently we wanted to create an ACFS filesystem on a brand new 12.1.0.2 GI installation on Oracle Linux 7.1. According to the documentation this should not be an issue as “Oracle Linux 7 with the Unbreakable Enterprise kernel: 3.8.13-33.el7uek.x86_64 or later” is supported. The “or later” is the important point. In our case: uname -a Linux racp1vm1 3.8.13-55.1.6.el7uek.x86_64 #2 SMP Wed Feb 11 14:18:22 PST 2015 x86_64 x86_64 x86_64 GNU/Linux   Should be fine as…

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Daniel Westermann

Testing the just released PostgreSQL 9.5 Alpha in a docker container

By | Database Administration & Monitoring | One Comment

On the 2cnd of July the PostgreSQL Global Development Group released an alpha version of the upcoming PostgreSQL 9.5. The same day, Josh Berkus, another of those PostgreSQL core team members released a docker image for testing this alpha release. It’s never been that easy to get started with PostgreSQL or testing new features. If you are on Linux the docker packages should be available for your distribution. For Oracle Linux 7.1 make sure that…

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Daniel Westermann

Indexing for like/similarity operations

By | Database Administration & Monitoring | One Comment

Indexing queries for like/similarity conditions is not that easy with the usual index types. The only option you have with btree indexes (especially if the wild-card is at the beginning of the filter) is to create a partial index on that columns for a very specific query. Let’s do a simple example with a btree index. The test data: drop table if exists t1; create table t1 ( a varchar(50) ); insert into t1 (…

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Daniel Westermann

Quickly create a hundred databases and users

By | Database Administration & Monitoring | One Comment

Do you need a hundred databases and users for training etc. in PostgreSQL? Just a few lines of code: [[email protected] data]$ cat create_databases.sh #!/bin/bash NUMOFDBS=100 for i in `seq ${NUMOFDBS}`; do psql -q -c “create user u${i} UNENCRYPTED password ‘u${i}’ NOCREATEDB NOCREATEROLE NOCREATEUSER” postgres createdb -O u${i} db${i} done Execute it and you are ready: [[email protected] data]$ time ./create_databases.sh real 1m37.825s user 0m0.143s sys 0m0.109s Have a look at the databases and its owners: postgres=#…

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Daniel Westermann

Swiss Postgres Conference 2015

By | Database Administration & Monitoring | No Comments

At the 26th of June I had the chance to attend the second Swiss Postgres Conference at the HSR Rapperswil. It was packed with interesting sessions. Magnus Hagander, a well known community member, started by giving an overview of PostgreSQL Europe. Then I joined Hans Schönig for learning how to write aggregate functions in PostgreSQL. Honestly I did not understand all of it but at least I am now aware of what you can do…

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