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 . Materialized views is a very old feature (you may remember that it was called snapshots a long time ago). It has all advantages of a view, as you can define any select statement that joins, filters, aggregates, and see it as one table. It has all advantages of a table, as it is stored in one…
By William Sescu If you think that Flashback Drop feature just brings back your table, then this is only half of the story. It does much more than that. Besides undropping the table, it also brings back your constraints, your indexes, your trigger, your grants and the statistics as well. The ugly part is, that the flashback drop brings back…
In my previous blog post, I talked about SQL Server on Linux and high availability. During my test, I used a NFS server to share disk resources between my cluster nodes as described in the Microsoft documentation. A couple of days ago, I decided to add a fourth node (LINUX04) to my cluster infrastructure and I expected to do this…
By William Sescu When I don’t need I feature, I don’t turn it on, or do not use it because it reduces the possibility to run into issues. Most of the times this is true, however, during the preparation for an RMAN workshop, the RMAN list failure command showed me the following dictionary issue. RMAN> list failure; using target database…
By Franck Pachot . Do you like DBCA to create a database from command line, with -silent -createDatabase? On a simple command line you can provision a database, with oratab, tnsnames.ora directory creation and any setting you want. And you can even call a custom script to customize further. But if you want to put it in Data Guard, you…
By Franck Pachot . In the latest post I’ve run a cached SLOB workload on Oracle Cloud IaaS to measure logical reads per seconds on a system covered by 2 processor licences (so 4 OCPs). Just as a comparison, here is the same on Oracle PaaS database as a service. PaaS The CPUs in PaaS are not exactly the same:…
This blog post comes from a very interesting discussion with one of my friends about the read-only capabilities of secondary replicas in the context of distributed availability groups. Initially, distributed availability groups are designed to address D/R scenarios and some migration scenario types as well. I already discussed about of one possible migration scenario here. However, we may also take…
By Franck Pachot . I’ve blogged recently about the Oracle Core Factor in the Clouds. And then, in order to optimize your Oracle licences, you need to choose the instance type that can run faster on less cores. In a previous blog post, I tried to show how this can be complex, comparing the same workload (cached SLOB) on different…
By William Sescu Relying to much on the RMAN Data Recovery Advisor is not always the best idea. In a lot of situations, it tells you the right things, however, sometimes it tells you not the optimal things, and sometimes, RMAN list failure does not show any failure at all, even if there is one. So … let’s simulate quickly…
By Franck Pachot . The Oracle PDBaaS is for database developers. And database developers may need to trace what happens with their queries: SQL trace and Optimizer trace. Let’s see what we can do on Exadata Express Cloud Service V$DIAG_TRACE_FILE_CONTENTS On the managed PDBaaS you don’t have access to the filesystem. But in 12.2 you have a view that can…
By William Sescu Not to often, but sometimes you need to offload your RMAN backups and your DataPump exports to CIFS. You might run out of space on your NFS server, or you are a Windows shop who has only CIFS shares, and then you might need to put your RMAN backups to CIFS. One very important MOS Note regarding…
By Franck Pachot . In Oracle Public Cloud, Transparent Data Encryption is not an option. You can use it because it is included in all database services for all editions. You have to use it because the database won’t allow you to create, or import, non encrypted tablespaces. This is controlled by a new parameter, encrypt_new_tablespaces, which defaults to CLOUD_ONLY;…
