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 . Various methods of table compression have been introduced at each release. Some require a specific storage system Some requires specific options. Some are only for static data. And it’s not always very clear for the simple reason that their name has changed. Name change for technical reasons (ROW/COLUMN STORE precision when a columnar compression has been…
By Franck Pachot . In the previous post I explained the performance issue encountered when using a generic query to deal with optional search criteria on multiple columns. The statement was shared by all executions, was marked as bind sensitive, but never became bind aware. Let’s use the BIND_AWARE hint. All binds null I assign null for all of them…
By Franck Pachot . You have a multicriteria search screen on the EMPLOYEE table where you can enter an employee id, a department id, a manager id or a job id. Either you put the value you want to filter on, or you leave it null when you don’t want to filter on it. How will you code that? You…
By Franck Pachot . RAC is the most complex installation you can have for an oracle database. A RAC DBA is involved not only on database, but storage, network, and system as well. It involves also the application in order to be sure that the application service can follow the database service high availability. It’s also brings every database skills…
By Franck Pachot . Enterprise Manager (Cloud Control for example) gathers a lot of metrics. You can display them from the GUI, but you can also query the SYSMAN views directly. Today, I wanted to get the history of free space in an ASM disk group for the previous week. Here is how I got it. Enterprise Manager metrics are…
By Franck Pachot . I’ve written about 12c online statistics gathering in a UKOUG OracleScene article. My opinion is clear about it: you sill need to gather stale stats afterwards or you have mising, stale and inconsistent object statistics. This post is about cases where online statistics gathering does not occur (and are not documented) – which is another reason…
By Franck Pachot . I’m using Oracle SQL Developer 4.1 Early Adopter for a while and I like it. That version comes with a command line (in beta) which goal is to be fully compatible with sqlplus but running in java, and having a lot more features. Becuse it’s connecting with thin java driver by default, it doesn’t use NLS_LANG.…
We saw in my last blog how to install the SQL Server plugin for Nagios. In this new blog, I will explain: how to create a wrapper to avoid the unset of the PERLLIB variable how to create and configure a configuration file by monitoring instance how to create an SQL Login for nagios How to subscribe to an alert…
I don’t work often with SQL Server replication. The main reason is that the number of customers that use replication is pretty low and each time that I have to deal with it, it’s a good opportunity to improve my skills on this area. A couple of months ago I had to face an interesting issue with the snapshot replication…
By Franck Pachot . There has been the announce that non-CDB is deprecated, and the reaction that CDB is not yet stable. Well. Let’s talk about the major issue I’ve encountered. Multitenant is there for consolidation. What is the major requirement of consolidation? It’s availability. If you put all your databases into one server and managed by one instance, then…
By Franck Pachot . In the previous post we have seen how the OracleText index tables are maintained when new document arrives: At sync the new documents are read up to the available memory and words are inserted in the $I table with their mapping information. Now we will see how removed documents are processed. We will not cover updates…
By Franck Pachot . I plan to write several posts about OracleText indexes, which is a feature that is not used enough in my opinion. It’s available in all editions and can index small text or large documents to search by words. When you create an OracleText index, a few tables are created to store the words and the association…
