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.
Oracle provides a monitoring console in the cloud but this console gives not all the information that we need. For example, it is not possible to send an email when a problem appear. However it is possible to use a Cloud Control on premise for monitoring this database. For that, it is necessary to have an EM12c release 5 and…
In all blogs that I read, the solution is just to change the retention period to a reasonable value. Yes, it is true but in some case you need to go deeper in the analysis… Like you, I changed the retention period, ran the cleanup but finally, I had always a big database… Why, Why, Why? My first step for…
As you certainly know, the well-known tool SQLIO is officially deprecated since few months. From my part, I had the opportunity (maybe the last) to use SQLIO for a customer project in order to benchmark the storage for SQL Server AlwaysOn and availability groups. Now it’s time to change for a new benchmark tool : DiskSpd. First of all, DiskSpd…
By Franck Pachot . In a previous post I presented how Dbvisit replicate can capture changes and write them in an audit table with old and new values. Here is how to do it wen you want only the new values – with same column names. What I want to get here is a table with: same column names as…
By Franck Pachot . I’m currently presenting at Swiss BI Day in Geneva about Oracle In-Memory option to improve analytic queries. Here are the slides, uploaded to SlideShare. http://fr.slideshare.net/pachot/oracle-inmemory-column-store-for-bi Don’t hesitate to comment here. Thanks a lot to the Swiss Business intelligence Network for the organization of the event.
By Franck Pachot . Next Tuesday in Geneva I’m presenting Oracle In-Memory Column Store to Business Intelligence people at the Swiss BI Day After defining what is an analytic query, I show the different approaches to optimize that in Oracle, IMCS being the latest one. Here are some details about that slide. What is an analytic query? First definition –…
By Franck Pachot . At our bi-annual dbiXchange I was talking with Nicolas Jardot about his presentation on Result Cache (don’t forget Jérome witt session about RC at DOAG) where he has shown an unexpected behavior on ‘fetch first n rows queries’. That behavior – if it is not a bug – can also be a good thing when using…
The new CTP 2.4 has been released and announced by Microsoft in its blog post a couple of days ago. During my investigation, I noticed some new installer capabilities about the tempdb database. As a reminder, you can read my first thoughts from my blog post here, but to be short, the installer was able to provide automatically the right…
By Franck Pachot . When you have a query failing in ‘ORA-01555: snapshot too old: rollback segment number … with name … too small’ you have two things to do: Convince the developer that the rollback segment is not too small because the message text comes from old versions Find information about query duration, undo retention and stolen blocks statistics.…
By Franck Pachot . It don’t want to rub salt in the wound about 12c upgrades and Adaptive Dynamic Sampling being overzealous, but here is a case with an unexpected consequence: you see nothing in the ‘Database Feature Usage’ since migration. The photo novel starts like this: we are in September and when I check the ‘Database Feature Usage’ page…
Why “also” in my title? On 29 August, my colleague Daniel Westermann wrote an article about Row Level Security in the next version of PostgreSQL. Row Level Security called also RLS is a new feature in SQL Server 2016 and of course in SQL Azure. This new security in SQL Server returns only rows that the user has permission to…
To be able to define which Tables or Stored Procedures will us the best performance gain after migration to In-Memory OLTP, SQL Server 2014 provided a tool called AMR (Analysis Migration and Reporting). This tool was really interesting but we should have, before to use it, to create a Management Data Warehouse and so on… (I wrote a blog here…
