Everything our consultants learn while running databases for customers: Oracle, PostgreSQL, SQL Server, MySQL, MariaDB, MongoDB and Delphix. Expect hands-on posts about installation, day-to-day administration, backup and recovery, performance tuning, replication and upgrades.
By Franck Pachot . You are using an Oracle Enterprise Edition and thinking about downgrading to the Standard Edition? In this case, you must be sure that your applications are compatible. It’s not something easy to check. Here are a few ideas. Why? Why do you want to downgrade to the Standard Edition? For licensing costs, of course. Today, it…
Installing and managing a highly available MySQL infrastructure can be really tedious. Solutions to facilitate database and system administrator’s task exist, but few of these cover the complete database lifecycle and address all the database infrastructure management requirements. Severalnines’ product ClusterControl is probably the only solution that covers the full infrastructure lifecycle and is also able to provide a full…
This post explains how to configure and use the new AWR warehouse functionality present in Enterprise Manager Cloud Control 12.1.0.4. This new feature offers the possibility to store date from the AWR of your main databases in the EM AWR warehouse. As OEM AWR warehouse automatically extracts the AWR data of the database you have selected, there is no impact…
By Franck Pachot . With OMF datafiles, you don’t manage the datafile names. But how do you set the destination when you want to move them to another mount point? Let’s see how easy (and online) it works in 12c. And how to do it with minimal downtime in 11g. Testcase Let’s create a tablespace with two datafiles. It’s OMF…
By Franck Pachot . Your datafiles have grown in the past but now you want to reclaim as much space as possible, because you are short on filesystem space, or you want to move some files without moving empty blocks, or your backup size is too large. ALTER DATABASE DATAFILE … RESIZE can reclaim the space at the end of…
By Franck Pachot . When you load data in direct-path and have the NOLOGGING attribute set, you minimize redo generation, but you take the risk, in case of media recovery, to loose the data in the blocks that you’ve loaded. So you probably run a backup as soon as the load is done. But what happens if you have a…
Since Oracle 10g, Oracle provides a great tool to import and export data from databases: Data Pump. This tool offers several helpful options, particularly one that allows to import data in a different tablespace than the source database. This parameter is REMAP_TABLESPACE. However, how can you do the same when you cannot use Data Pump to perform Oracle import and…
By Franck Pachot . Recently, I described the Partial Join Evaluation transformation that appeared last year in Oracle 12c. I did it as an introduction for another transformation that appeared long time ago in 10.1.0.3 but was not used by default. And even in the latest Oracle 12c patchset 1 (aka 12.1.0.2.0) it is still not enabled. But it’s there…
While working on a customer project, I needed to retrieve the SQL Server SCOM Management Pack version. Unfortunately, the SCOM team took a while to answer and as I am the DBA, I have access to the SCOM databases. So let’s have a look at how we can get this the “hard” way. On 30/06/2014, a new Management Pack was published…
Deploying an SQL Server database to a Windows Azure virtual machine is a feature introduced with SQL Server 2014. It can be useful for an organization that wants to reduce its infrastucture management, simplify the deployment, or have a fast virtual machine generation. Concept This new feature is a wizard which allows either to copy or migrate an On-Premise SQL…
Have you noticed an interesting behavior with SQL Server 2014 when you are running a dbcc checkdb command? If not, you should have a look at this blog post. I discovered it completely by accident during some tests. If you watch carefully, you will see “weird” files appear while the dbcc checkdb command is running. Below is a sample of…
By Franck Pachot . When an Oracle Database spends a high percentage of its DB time in User I/O, I usually check the wait event histograms in order to see if the storage system is working well. But today, with storage going to SSD, most I/O are less than 1 milliseconds and we have no details about those wait times.…
