Author Archives: George Valentin Voina

EdgeRouter: OpenVPN site-to-site performance

By | March 30, 2016

As a result of setting up my site-to-site VPN see this it is much easier to transfer things from one site to the other. The questions that came to mind were: What is the bandwidth of my VPN ? What is the limiting factor ? My ISPs or the Edge Router ? To answer to… Read More: EdgeRouter: OpenVPN site-to-site performance »

DB2: Find a foreign key

By | February 8, 2017

Sometimes working with Hibernate you get the following error in case a persist is executed on an object with dependencies. com.ibm.db2.jcc.am.SqlIntegrityConstraintViolationException: Error for batch element #1: The insert or update value of the FOREIGN KEY “INST1.MESSAGE.FK_1FUTL48XT47HPPGH0YXQM1MIJ” is not equal to any value of the parent key of the parent table.. SQLCODE=-530, SQLSTATE=23503, DRIVER=4.13.127 From IBM… Read More: DB2: Find a foreign key »

Oracle: Finding and adding indices

By | February 8, 2017

Sometimes things go slow in the database even if the original setup was done with a lot of care. The data traffic the usage of the application can sometimes impose the need of extra indices in addition to the original indices added by the enterprise application client that uses the Oracle database. The following procedure… Read More: Oracle: Finding and adding indices »

Microsoft SQL Server: Database Replication (Mirroring)

By | October 25, 2017

Microsoft SQL Server Standard Edition has a great feature present in this basic license: Database Replication in Synchronous mode. To activate the database replication of a database from Primary Site (PR) to Disaster Recovery Site (DR) where the database to be replicated is called myDB the following simple steps must be performed: On PR site… Read More: Microsoft SQL Server: Database Replication (Mirroring) »

Microsoft SQL Server: Snapshot isolation

By | February 9, 2017

Snapshot isolation is a guarantee that all reads made in a transaction will see a consistent snapshot of the database. The transaction itself will successfully commit only if no updates it has made, conflicts with any concurrent updates made since that snapshot. By using it, deadlock situations when a read operation (intense resource consuming operation)… Read More: Microsoft SQL Server: Snapshot isolation »

EdgeRouter POE: Power 48V POE switches

By | May 25, 2016

I got my EdgeRouter POE from UbiQuiti EdgeRouter, 5-port Router POE and came with the 24VAC power supply. Because the Ubiquity devices are all using the strange low power POE for which 24VAC is enough they ship the EdgeRouter POE with the 24VAC power supply. As a result the device is useless in powering “normal”… Read More: EdgeRouter POE: Power 48V POE switches »

Owncloud 8.1.5: File upload error Table ‘homeclouddb.oc_locks’ doesn’t exist”

By | February 9, 2017

After an OwnCloud upgrade I was getting complains from my users that WebDav and OwnCloud windows client were no longer able to upload files. By looking into owncloud.log the following was the repeated error: {“app”:”remote”,”message”:”An exception occurred while executing ‘SELECT * FROM `oc_locks` WHERE `userid` = ? AND (`created` + `timeout`) > 1456517102 AND ((… Read More: Owncloud 8.1.5: File upload error Table ‘homeclouddb.oc_locks’ doesn’t exist” »

Internet: Subresource Integrity (SRI)

By | February 9, 2017

Yes our friends from China invented a new type of DDOS attack. The great firewall changed unencrypted traffic that contained 3rd party javascript libraries to DDOS GitHub. There is already a testing tool SRI Test developed and deployed by Gabor Szathmari see for more details his blog To protect my blog I found out that… Read More: Internet: Subresource Integrity (SRI) »