There are times when even experimented sysadmins do stupid things. One of that moments happened to me when I tried some speed tests on my ssd RAID1. The result was not so satisfactory. Corrupted /boot partition with missing files and orphan inodes. To make things more complicated I have the following constraints that make this… Read More »
This error is the DB2 cryptic way of informing you that a value which an insert query tries to insert in a table is too large. Usually when using java + hibernate we can define a member of an EJB as: @Column(length = 10) protected String receiver; If somehow when the object is created we… Read More »
Keeping the installation of your own WordPress blog highly secure is very important. In today’s fast pace discovery of security vulnerabilities you must keep an eye on all the new security threats and update as soon as possible the security to try to cover the new threat. An invaluable tool is the security test from… Read More »
From a very strange reason after updating the hibernate4 from version 4.1.4 to 4.2.5 there was suddenly a weird behaviour of the EJB3.1 enterprise application I am working on. A piece of code that commits to the database an object (ProcessingStatus) containing a BLOB was throwing the following: [1/31/16 23:37:15:922 EET] 000000eb AbstractBatch Z org.hibernate.engine.jdbc.batch.internal.AbstractBatchImpl… Read More »
This is an annoying issues of hibernate with DB2. Trying to add a new primitive type to an already existing entity will result in an error when updating the associated database table. As a result no update of the schema is done. Why is that ? When adding to an entity a new primitive type… Read More »
As I mentioned in a previous post I started looking into upgrading my Dell XPS 8700 see https://blog.voina.uk/?p=325. One of the possibilities I mentioned there was a memory upgrade from the 16GB of the original configuration to the maximum of 32GB. By doubling the memory size I can run a 4th instance of my Fedora… Read More »
Red Hat Enterprise Linux allows administrators to bind multiple network interfaces together into a single channel using the bonding kernel module and a special network interface called a channel bonding interface. Channel bonding enables two or more network interfaces to act as one, simultaneously increasing the bandwidth and providing redundancy. The behaviour of the bonded… Read More »
As we now in case of a table with BLOBs in the actual table row only a reference to the BLOB is stored. In order to get the real table size of my table ‘MY_BLOB_TABLE’ including the refereed BLOBs the following query holds in Oracle: SELECT sum( bytes)/1024/1024 size_in_MB FROM user_segments WHERE (segment_name = ‘MY_BLOB_TABLE’… Read More »
Sometimes an oracle query goes nuts and blocks the DB. To find the blocked processes started by user MYUSER execute: SELECT s.inst_id, s.sid, s.serial#, p.spid, s.username, s.program FROM gv$session s JOIN gv$process p ON p.addr = s.paddr AND p.inst_id = s.inst_id where s.username like ‘MYUSER’; To kill the blocking process: ALTER SYSTEM KILL SESSION ‘sid,serial#’
LOBS is the DB2 way of dealing with big data. In db2 you can have a table that contains a column defined as LOB where one can dump large binary data (images, compressed text files, video or audio). The problem is the way this LOBS are stored by DB2. By default they are stored “offline”… Read More »