Infrastructure at your Service
As you might now if you are following our blogs (see this one for example), we are using Alfresco Community Edition internally for some years now and we also have a few customers using it. Today, I will present you a small issue I faced with Alfresco which wasn’t able to display the content of a few – very specific – folders… As you will see below, it was actually not related to Alfresco but…
In this blog I am going to test the extension mimeo with PostgreSQL 10 beta. Mimeo is a replication extension for copying specific tables in one of several specialized ways from any number of source databases to a destination database where mimeo is installed. In our configuration we are going to replicate data on a same server but between 2 clusters running on different ports. But it’s same for different servers. The pg_hba.conf should be…
There are 4 models of Oracle Database Appliance with the new ODA X6 which is for the moment the latest ODA hardware version. One is similar to the previous X5-2 one, and 3 smaller ones known as ODA Lite. They are 1 year old already, here is a small recap of the differences and links to more detail.
When working with WebLogic, there will probably be a moment when you will ask yourself: damn, what is wrong? Nowadays, software are so complex that it is kind of easy to introduce bugs/non-wanted behaviors in them… In this blog, I will present a small thing that just blew my mind when I faced it: I had a fully working WLS on which I executed a WLST script in order to configure the SSL Ciphers for…
By accident, it could happen that someone dropped an OUD entry in your replicated environment and of course, the entry is deleted on all replicas as well. And besides that, you got no logical ldif export of your OUD. Not a good situation, but if you have a done regular backups, there is a way out without resetting the whole OUD environment to an old timestamp. The idea is, to create a second empty OUD…
In the previous post my queries were still reading the indexed column only, from a table which had no modifications since the last vacuum, and then didn’t need to read table pages: it was Index Only Scan. However, we often need more columns than the ones that are in the index. Here is the Index Scan access path.
A couple of months ago, Microsoft announced two additional command line tools for SQL Server that are mssql-scripter and DBFS. The latter has drawn my attention because it exposes live data from SQL Server DMVs as virtual files in a virtual directory on Linux operating system. Microsoft has probably taken another positive step in the SQL Server’s adoption on Linux. Indeed, in a Linux world, we may get Kernel’s performance and configuration data either directly…
A lot of possibilities exist to migrate MySQL to MariaDB. In this blog I would like to show a scenario where I migrate MySQL 5.7.19 with a lot of databases to MariaDB 10.2.7, which is on a different host. The tools I am using are mydumper/myloader and ncat. Please be aware that mydumper does not come out of the box. It has to be installed beforehand, like explained in my previous blog: https://blog.dbi-services.com/mariadb-speed-up-your-logical-mariadb-backups-with-mydumper/ The same…
We have seen how an index can help to avoid a sorting operation in the previous post. This avoids a blocking operation: the startup cost is minimal and the first rows can be immediately returned. This is often desired when displaying rows to the user screen. Here is more about Postgres startup cost, Oracle first_rows costing, and fetching first rows only.
The 2nd edition of 24HOP French Edition 2017 is over and we had great sessions about SQL Server and various topics ( SQL Server 2017 new features, Azure, PowerBI, High Availability , Linux, Hyper-convergence , Modeling …) If you did not attend to this event, you now have the opportunity to watch the videos of the different sessions. From my side, I had the chance to present SQL Server and High Availability on Linux. Hope to…
Per default, MariaDB is shipped with a utility called mysqldump for logical backups. For more information, please take a look at the following link. https://mariadb.com/kb/en/mariadb/mysqldump/ The mysqldump has advantages, e.g. it is easy to use and it is shipped with the standard MariaDB installation. So, no additional installation is needed. However, it has also some disadvantages. E.g. it is single threaded and it is writing to one big file, even with the latest version which…
I realize that I’m talking about indexes in Oracle and Postgres, and didn’t mention yet the best website you can find about indexes, with concepts and examples for all RDBMS: http://use-the-index-luke.com. You will probably learn a lot about SQL design. Now let’s continue on execution plans with indexes. As we have seen two posts ago, an index can be used even with a 100% selectivity (all rows), when we don’t filter any rows. Oracle has…
