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Database

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.

ODA fiber interface link detection issue

Configuring fiber interfaces during an ODA installation can sometime been challenging. The configuration can depend on the kind of gigabit interface converter (GBIC) and switch been used. In this blog, I would like to show a real case faced during one of our customer deployment, and come with a solution. Problem We were facing link detection issue when using the… 

18c: some optimization about redo size

By Franck Pachot . Some years ago, at the time of 12.1 release, I published in the SOUG newsletter some tests to show the amount of redo generated by different operations on a 10000 rows table. I had run it on 12.2 without seeing the differences and now on 18.1 I get the statistics from mystat using a script that… 

Event Sourcing: CQN is not a replacement for CDC

By Franck Pachot . We are in an era where software architects want to stream the transactions out of the database and distribute them, as events, to multiple microservices. Don’t ask why, but that’s the trend: store inconsistent eventually consistent copies of data in different physical components, rather than simply using logical views in the same database, where the data… 

Statspack installation scripts

By Franck Pachot . When Diagnostic Pack is disabled, either because you don’t have Diagnostic Pack or you are in Standard Edition, I highly recommend to install Statspack. When you will need it, to investigate on an issue that occured in the past, you will be happy to have it already installed and gathering snapshots. I order to be sure… 

DataGuard and Transparent Data Encryption

By Mouhamadou Diaw Setting up a DatagGard environment for a database with Transparent Data Encryption requires some tasks concerning the encryption keys. Otherwise the steps are the same than for an environment without TDE. In this blog we will present the tasks we have to do on both primary and standby servers for the keys. We will not describe the… 

PGIO, PG_STAT_ACTIVITY and PG_STAT_STATEMENTS

By Franck Pachot . For an Oracle DBA, we are used to join active sessions (from V$SESSION where status=’ACTIVE) with active statements (from V$SQL where users_executing>0) on the SQL_ID. V$ACTIVE_SESSION_HISTORY also displays the TOP_LEVEL_SQL_ID to get the entrypoint of the usercall if we need it. With Postgres it is a bit more difficult because it seems that PG_STAT_ACTIVITY do not… 

Lighty for PostgreSQL

By Franck Pachot . If you follow this blog, you should know how I like Orachrome Lighty for Oracle, for its efficiency to monitor database performance statistics. Today Orachrome released the beta version of Lighty for Postgres: https://orachrome.com/news/la-beta-de-lighty-for-postgresql-est-ouverte/ The Cloud is perfect to do short tests with more resources than my laptop, especially the predictability of performance, then I started… 

Oracle Virtual Private Database

By Mouhamadou Diaw Oracle Virtual Private Database (VPD) enables you to dynamically add a WHERE clause in any SQL statement that a user executes. The WHERE clause filters the data the user is allowed to access, based on the identity of a user. This feature restricts row and column level data access by creating a policy that enforces a WHERE… 

Kernel panic – not syncing: Out of memory and no killable processes

By Franck Pachot . This is a quick post to give a solution (maybe not the best one as this was just quick troubleshooting) if, at boot, you see something like: Trying to allocate 1041 pages for VMLINUZ [Linux=EFI, setup=0x111f, size=0x41108d01] and then: Kernel panic – not syncing: Out of memory and no killable processes Pid: 1228 comm: kworker Not… 

Introduction to databases for {Power.Coders} with MySQL

By Franck Pachot . This week I took some days off to do something related to my job but a bit different. I’ve given a course on Databases and SQL. But not for my usual customers. And not with the database I know the best. So, it is still in a domain that I know, but out of my comfort…