Jump to Navigation

Recently created

Nouveau driver not loaded

After experiencing some X11-crashes, it turns out that X11 was using the modesetting driver instead of Nouveau. For some reason my Debian configuration was not selecting the driver I needed.

If you inspect your X log-file (usually /var/log/Xorg.0.log) and look for Modeline entries, the log lines will start with modeset(0) if you are using the modeset driver, and with NOUVEAU(0) if you are using the Nouveau driver.

Firefox: You've launched an older version

After upgrading my workstation to buster, Firefox insisted on creating a new profile:

The new version was 68.2, the old version too, but Firefox kept complaining.

The solution: create a new profile, close Firefox and compare ~/.mozilla/firefox/*/compatibility.ini. Copy the LastVersion setting from your new to your old profile. Now Firefox is happy to use your old profile again.

A strange Java OPatch error

After installing a new version of OPatch on an Oracle database home, I got the somewhat mystifying error:

The java.library.path system variable is missing or invalid. Please set java.library.path with a correct value and retry the operation.

It turns out this is the error you get when you install a 32-bit version of OPatch into a 64-bit Oracle home.

Missing ports and rpcinfo

I was making an inventory of the bound ports on my server, when I encountered a rather strange situation: a high port that was not associated with any process.

The easiest way to find sockets like that is with:

MySQL: Check table engines in use

To determine whether tables in your MySQL database use MyISAM or InnoDB, you can use the following query:


This shows all engines used for each database. Most tables will use either MyISAM or INNODB, but there are other engines, like MEMORY, CSV and PERFORMANCE_SCHEMA.

Create database fails on package STANDARD

While scripting the creation of an Oracle database, I somehow kept getting errors during the CREATE DATABASE:

ORA-06553: PLS-213: package STANDARD not accessible

Very weird. Until I realized I was using a generic scripting function that issued a SET SERVEROUTPUT ON. It turns out that Oracle can not cope with that until you have loaded catalog.sql and catproc.sql.

xs4all VDSL with the Vigor 130

I am back on a slowish VDSL home connection. After getting used to high-speed fibre, this is quite a set back. My provider is xs4all. They provide a Fritzbox 7360 v2 modem. It used to be that you could set these to bridge the VDSL signal to your ethernet, but this is no longer possible for recent firmwares.

Talking to Grid Control

And suddenly, Firefox did not want to connect to Oracle Grid Control anymore.

The error message displayed was Cannot communicate securely with peer: no common encryption algorithm(s). (Error code: ssl_error_no_cypher_overlap). Google was not immediately useful (suggesting things like turning off SSL).

MySQL: Administering replication

Replication threads

Replication uses two slave threads. One is the I/O thread: it connects to the master server, downloads transactions and writes them to the relay logs. The other is the SQL thread: it reads transaction from the relay logs and executes them.

Provided the network connection between master and slave is stable, any bottlenecks are in the SQL thread. On a very busy system it can lag behind the I/O thread.

MySQL: Binlogs

You have to use binlogs for three reasons: when this server is a master to a slave, when this server is part of a replication structure using GTIDs or when you want to be able to do point-in-time recoveries.

A slave uses the binlogs of the master for replication. If you are not using GTIDs, the master binlogs are read sequentially and each non-filtered transaction is applied. The position in the master binlogs of the slave is thus very important.


Subscribe to Recently created

by Dr. Radut