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.
When you are working on Oracle you probably learned that each DDL does an implicit commit in the background. There is no way to have DDLs wrapped in a real transaction (with the exception of the “create schema” command which I blogged about a long time ago). If you take a look a the SQL:2008 standard (ISO/IEC 9075-1:2008) you can…
By Franck Pachot . When you want to transport a SQL Tuning Set between production and test for example, you have to pack it into a table, then export the table, import it into the target database, and unpack the STS. This is a case where Enterprise Manager can help to do it quickly. First I create a SQL Tuning…
While doing a project at a customer we came to a point where we needed to install pl/java into Postgres Plus Advanced Server 9.5. If you follow the official documentation you will probably fail and get stuck when trying to build pl/java with maven (at least I did fail several times). Unfortunately there is not much documentation around for solving…
By Franck Pachot . I wanted to check if Exadata predicate offloading can occur on Global Temporary Tables. Actually, I thought it did not and I was wrong. I was ready to post that as an hypothesis for https://community.oracle.com/thread/3903836 but, before any post to forums, I try to test what I say because I may be wrong, or things may…
A couple of weeks ago, I had an interesting discussion with one of my customer about the page life expectancy (aka PLE). He asked me if monitoring the metric value is a best practice because he often noticed a big drop of the PLE under the recommended threshold during the night or sometimes during the business hours. In addition, he…
Last time, I experienced a strange error when I tried to perform an integrity check or a simple checkpoint of a database: One or more recovery units belonging to database ‘mydatabase’ failed to generate a checkpoint. This is typically caused by lack of system resources such as disk or memory, or in some cases due to database corruption. Examine previous…
By Franck Pachot . From 12.1.0.2 the Standard Edition – now called Standard Edition 2 – has a few limitations that were not there in SE and SE1. One of them is the limitation to 16 threads. Let’s see how it behaves when running 32 sessions working in CPU. Installing 12.1 SE2 on a 32 CPU host. What to provision…
This time let’s talk about an interesting customer scenario where table partitioning was implemented on a table with 100 GB of data on SQL Server 2014. Partitioning in this context aimed to save disk space (archive data were compressed) , help to reduce maintenance time and consumed resources as well (by using index and statistic maintenance operations on the active partition). Finally,…
As the Enterprise Manager Cloud 12c is configured for sending warnings and alerts if a target database is down, what’s happening if the Enterprise Manager Repository database crashes? With Enterprise Manager Cloud Control 12c, a quite good solution is available: after an easy configuration, the management agent is able to run script to notify database administrators there is a problem with…
At a client’ site I decided to install the Enterprise Manager Cloud Control 13c. I did not encountered any special problem :=) , then I installed an agent 13c on the development plattform and added targets as usual, but at this timeI discovered that half of my database targets in 11.2.0.3 version were in the following state : 2016-02-05 15:31:46,863 [2527:A154C6AD]…
By Franck Pachot . Oracle provides lots or parameters that can control the behavior of the software. The default values are probably the best ones most of the time. Hundreds of parameters are documented and we can set them to customize the Oracle software for our context because default values can’t fit all different database sizes, usage, workload, infrastructure, etc.…
By Mouhamadou Diaw Last day I found a curious message in the backup alert log in a dataguard environment. The message was related to an issue with the resync catalog and was something like 1 2 3 4 RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS =============== RMAN-00571: =========================================================== RMAN-03009: failure of resync command on default channel at 02/18/2016 17:48:42 ORA-00001: unique…
