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.
In the last post we had a look at how you can configure huge pages on RedHat and CentOS systems. For Debian and Debian based systems the procedure is different as Debian does not come with tuned. Lets see how it works there. Checking the basic system configuration works the same in Debian as in RedHat based distributions by checking…
Almost every PostgreSQL I get in touch with is not configured to use huge pages, which is quite a surprise as it can give you a performance boost. Actually it is not the PostgreSQL instance you need to configure but the operating system to provide that. PostgreSQL will use huge pages by default when they are configured and will fall…
A recent commit announced new SHA-2 functions coming up in PostgreSQL 11. Until now you can use the md5 function to generate hashes for test data or whatever you want. This commit adds more functions you can use for that. Let’s see how they work. When you want to try what follows make sure you are on the development version…
My Linux experience started back in 1999 when we needed a router for our ISDN connection in our shared apartment when we were students. I don’t remember the hardware we used for that but I am sure at that time it was a SUSE operating system. Not sure about the version, but based on this it must have been version…
Recently we had the situation that the Veritas cluster (InfoScale 7.3) showed interfaces as down on the two RedHat 7.3 nodes. This e.g. can happen when you change hardware. Although all service groups were up and running this is a situation you usually want to avoid as you never know what happens when the cluster is in such a state.…
Docker becomes more and more popular these days and a lot of companies start to really use it. At one project we decided to build our own customized Docker image instead of using the official PostgreSQL one. The main reason for that is that we wanted to compile from source so that we only get want is really required. Why…
Today I had the pleasure to have Bruce Momjian in my session about PostgreSQL Upgrade Best Practices at the IT Tage 2017 in Frankfurt. While browsing through the various options you have for upgrading there was one slide where I claimed that the old cluster needs to be down before you run pg_upgrade in check mode as you will hit…
DISCLAIMER: I know it exists other solutions to do it Pre-requisites: – a virtual machine (or not) with CentOS7 installed – a free disk or partition I use a VBox machine and I added a 5GiB hard disk We list the disk and partition to check if our new hard is added. [root@deploy ~]$ lsblk NAME MAJ:MIN RM SIZE RO…
As you probably noticed RedHat as well as CentOS switched to systemd with version 7 of their operating system release. This also means that instead of looking at /var/log/messages you are supposed to use journcalctl to browse the messages of the operating system. One issue with that is that messages before the last reboot of your system will not be…
While giving the last PostgreSQL DBA Essentials workshop this question came up: When we create a table or an index: are the statistics available automatically? To be more precise: When we create and load a table in one step, create an index on that table afterwards: Do we have the statistics available by default or do we need to wait…
In PostgreSQL when you create an index on a table, sessions that want to write to the table must wait until the index build completed by default. There is a way around that, though, and in this post we’ll look at how you can avoid that. As usual we’ll start with a little table: postgres=# \! cat a.sql drop table…
You might wonder, but yes, Veritas is still alive and there are customers that use it and are very happy with it. Recently we upgraded a large cluster from Veritas 5/RHEL5 to Veritas InfoScale 7.3/RHEL7 and I must say that the migration was straight forward and very smooth (when I have time I’ll write another post specific to the migration).…
