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 . The RAC Attack – install a RAC in your own laptop – is a great success at Las Vegas. The idea is to help people follow the RAC Attack cookbook which is available at: http://en.wikibooks.org/wiki/RAC_Attack_-_Oracle_Cluster_Database_at_Home/RAC_Attack_12c/Hardware_Requirements It is a complex configuration and there is always problems to troubleshoot: get Virtual Box be able to run a 64-bits…
By Franck Pachot . A frequent question about replication is the overhead in the source, because in a lot of cases the source is production. Dbvisit replicate comes with the possibility to do the minimum on the source: only the FETCHER process is there to read de redo logs and sends it to the MINE process wich can be on…
By Franck Pachot . There are several new features in 12c about Data Guard: cascaded standby, far sync instance. But there are also some architecture changes: new processes and new wait events. Here is an example of an AWR report of a LogXptMode=’SYNC’ DataGuard configuration in 11g – which means that the log_archive_dest is defined with: ‘LGWR SYNC AFFIRM’ That…
By Franck Pachot . You have read all Cary Millsap work about Oracle database performance tuning. You know that there are no silver bullets. Reducing the response time requires a methodical approach in order to analyze the response time with the goal of eliminating all unnecessary work. But I’ll show something completly opposite here. A performance tuning silver bullet. Do…
By Franck Pachot . In a previous post I’ve shown that from 12.1.0.2 when you have an index on trunc(date) you don’t need additional index. If you need the column with full precision, then you can add it to the index on trunc(). A comment from Rainer Stenzel asked if that optimization is available for other functions. And Mohamed Houri…
By Franck Pachot . The Oracle Database Appliance is really interresting for small enterprises. It’s very good hardware for very good price. It’s capacity on demand licensing for Enteprise Edition. But small companies usually go to Standard Edition for cost reasons. Then does it make sense to propose only Enterprise Edition to the small companies that are interrested by ODA?…
This new feature has been introduced in SQL Server 2012 and needs an Enterprise Edition. It uses a Windows Service which scans Oracle Logs and tracks DML changes from Oracle tables into SQL Server change tables. In other words, Change data capture records Insert, Update and Delete activities that is applied to Oracle tables. Let’s see how it works. Prerequisites…
In our more and more connected world, security is a big concern. Storing password is a very important topic because if a machine is compromised, we can assume that any password stored in clear text are also compromised. I had the question from a customer how can we encrypt the password in our application and monitoring scripts? In this blog…
By Franck Pachot . Can we shutdown abort a PDB? Let’s try: SQL> show con_id CON_ID —————————— 3SQL> shutdown abort; Pluggable Database closed. But is it really a shutdown abort? The shutdown abort we know in non-CDB – or in a CDB from CDB$ROOT – is used when the instance cannot checkpoint before closing the file. It leaves the files…
By Franck Pachot . Sometimes we have to index on ( trunc(date) ) because a SQL statement uses predicate on it instead of giving a range from midnight to midnight. When you do that you probably keep the index on the column. That’s two indexes to maintain for DML. Do we need it? I’ll show a feature that appeared in…
Since version 12, ODA stores databases on ACFS volumes instead of ASM directly. This slightly changed the way the files are managed and administer. This articles presents how to multiplex your control files on ACFS. At first database creation, ODA set up 3 ACFS volumes to store all non-CDB databases (CDB are managed on dedicated volumes): /dev/asm/datastore-386 62G 5.2G 57G…
Have you ever attempted to bulk import a SQL Server error log in order to use the information inside a report for example? If yes, you have probably wondered how to keep data in the correct order in a query because you cannot refer to any column from the table. In such case you can notice that you may have…
