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 William Sescu Oracle incrementally updating backups are used quite often because they are easy to setup and restoring a datafile is very fast. It is very fast because you are not really restoring a datafile, you are switching to the copy, in case something happens. But how do I switch back to the original destination with minimal downtime and…
By Franck Pachot . In a previous post I described the new V$SQL views about rolling invalidation. I did the example with dbms_stats which is able to do rolling invalidation since 11g. But more is coming with 12.2 as you can use rolling invalidation for some DDL. When you do some DDL on an object, dependent cursors are invalidated. On…
In the last posts in this little series we looked at how to get a ZFS file system up and running on a CentOS 7 host and how snapshots and clones can be used to simply processes such as testing and cloning PostgreSQL instances. In this post we’ll look at another feature of zfs: Compression. The current status of my…
By William Sescu A lot of new features popped up with RMAN 12c, like Expansion of Multi-section support, or Simplified cross-platform migration and many many more. However, in this post I would like to highlight a small, but very helpful new feature which I demonstrated during my session at the SOUG day. The automatic datafile creation In earlier versions of…
In the last post we looked at how to get a ZFS file system up and running on a CentOS 7 host and how to enable the auto mount of the ZFS file systems. In this post we’ll look at two of the features ZFS provides: Snapshots and clones. A ZFS snapshot is a read only copy of a file…
ZFS for Solaris is around for several years now (since 2015). But there is also a project called OpenZFS which makes ZFS available on other operating systems. For Linux the announcement for ZFS being production ready was back in 2013. So why not run PostgreSQL on it? ZFS provides many cool features including compression, snapshots and build in volume management.…
Some time ago I blogged about attaching your PostgreSQL instance to an Oracle database by using the oracle_fdw foreign data wrapper. This resulted in a comment which is the reason for this post: Doing the same with a Debian system where you can not use the rpm versions of the Oracle Instant Client (at least not directly). Lets go ……
Did you ever consider an index seek as an issue? . Well, let’s talk about a story with one of my customers where the context is pretty simple: a particular query that is out of the range of the application’s performance requirements (roughly 200ms of execution time in average). The execution plan of the query was similar to what you…
By Franck Pachot . In a previous post I published a test case to show when a cursor is not shared anymore after a rolling invalidation. Basically the dbms_stats marks the cursor as ‘rolling invalid’ and the next execution marks it as ‘rolling invalid executed’. Looking at 12cR2 there is a little enhancement in V$SQL with an additional column displays…
By Franck Pachot . This blog post is focused at developers and software architects. I’m probably not writing at the right place. You’re on an infrastructure experts blog and the author is an Oracle DBA. So what can you learn from someone working on that 30 years old technology talking about that old SQL language ? You run with modern…
Last week (09/12/2016) was announced the new MySQL 8.0.0 DMR (Development Milestone Release) It is now available for download at dev.mysql.com I downloaded and installed it Following are my first impression on some new features First of all, when you remember the size of earlier versions, it is more & more gluttonous, see below mysql-5.0.96-linux-x86_64-glibc23.tar.gz 121.2M mysql-5.1.72-linux-x86_64-glibc23.tar.gz 127.8M mysql-5.5.52-linux2.6-x86_64.tar.gz …
By Franck Pachot . I’m at Oracle Open World and I’m rather focused on database rather than all those Cloud topics, but one product caught my attention at the Oracle ACED Briefing. Oracle bought Ravallo systems at the beginning of the year. What is Ravello? You have virtualized your applications on VMware and want to move them to the Cloud……
