Posts published under the Open source Team account are collective contributions by the dbi services open infrastructure consultants. The practice covers open-source databases and platforms, PostgreSQL first of all, along with MySQL, MariaDB, and Linux, from architecture, replication, and high availability to performance tuning and operations under service level agreements, and contributes actively to the PostgreSQL community.
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…
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…
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…
Do you need a hundred databases and users for training etc. in PostgreSQL? Just a few lines of code: [postgres8@oel7 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${i} done Execute it and you are ready: [postgres8@oel7 data]$ time ./create_databases.sh real…
How often did I type a query like this to list the invalid objects in a database? select count(*) from dba_objects where status ‘VALID’; — and user in/not in Today I learned another way to do the same. There is a view called dba_invalid_objects. Surprisingly the view is not listed in the official 12c database reference. It is however mentioned…
As I am still interested in PLSQL I browsed the documentation some days ago and learned something new which is about functions returning collections. Here is a simple test case: Let’s create a simple package, specifying on collection and one function: create or replace package pkg1 as type t1 is table of number index by pls_integer; function f1 ( a…
On the 16th and 17th of June David Hueber, Georges Grey and myself had the chance to attend the ODA hands on workshop at Arrow ECS. Lead Trainer Ruggero Citton (Oracle ODA Product Development) did the first day with plenty of theory and examples. On the second day we had the opportunity to play on a brand new ODA X5-2:…
In the last post on this topic it turned out that using an array as a column type needs more space than using a column per value in PostgreSQL. Now I’ll do the same test case in Oracle. As with the PostgreSQL test case I’ll create two test tables in Oracle: One using 10 columns and one just using one…
In PostgreSQL ( as well as in other rdbms ) you can define columns as arrays. What I wondered is: What is more efficient when it comes to space: Creating several columns or just creating once column as array? The result, at least for me, is rather surprising. First, let’s create a table with columns of type int: postgres=# create…
The PostgreSQL psql utility provides some really nice features. One of these features is SQL interpolation which allows us to do interesting things, e.g. reading files and analyze the results directly in the database. This post will show how to use this by reading and analyzing sar files of a linux server. Usually linux hosts store sar statistics in the…
Recently I was looking for a free PostgreSQL cloud database service for testing. Why? Because I’d like to use such a cloud instance for testing no matter on which workstation or OS I am currently on. Another reason is, that I could could prepare some demos at home and use the same demos at work without needing to worry about…
What a surprise: Headed over to the sourceforge page, downloaded, installed (which is just a matter of next/next/next) : Not really the latest patchset but far more than I expected 🙂 So I can do tests on a Windows machine where I do not have any permissions to install software. Great. If you prefer a graphical client then go ahead…
