Data-intensive transactions – which is the right database technology?

Cost savings with PostgreSQL: efficient resource allocation through alternative database technology

Gallinat-Service GmbH is a wholly-owned subsidiary of Gallinat-Bank AG and, as a group-owned service provider, manages the areas of asset backed securities, factoring and structured corporate finance both for external clients and for all the companies within the parent group of Gallinat Bank AG, the ALBIS Leasing Group. The ten-member Gallinat Service Team has developed its own Java-based software platform to meet all monitoring and processing requirements relating to ABS and factoring transactions: The epAAA securitization software, certified by BDO to PS 880, is financial software used in banking for posting, settlement and risk reporting in connection with accounts receivable purchasing. Typical applications are securitization transactions and factoring refinancing. Data on receivables and postings relating to sellers of receivables is compiled into a monthly investor report via the connected Web reporting portal. In addition to mapping all the financial accounting for the SPV and the processing of all standard posting activities for all parties to a transaction, individual client-specific posting activities and accounts can be added to the solution at any time. 

Annual licensing increases under review
Data-intensive transactions – which is the right database technology? Originally, the epAAA settlement software and the reporting portal were operated using an Oracle database to ensure sufficient capacity for the data-intensive processing. However, the cost/benefit ratio of the Oracle database deteriorated due to annual increases in licensing costs. The implementation of the reporting portal pushed the licensing costs up further owing to the number of external reporting portal users that are involved in the Oracle license model. This meant that using the Oracle database was no longer justifiable when compared with in-house controlling. This prompted the decision to switch to an alternative open source database software across the whole group.

Reliability of PostgreSQL
Other applications based on the open source object-relational database management system PostgreSQL were already running at this time in the ALBIS Leasing Group. The company's experience with regard to the reliability of the PostgreSQL software was extremely positive. Frank Ebinger, Head of IT Engineering at Gallinat-Service GmbH and responsible for the database migration, said PostgreSQL had an extremely positive image throughout the entire group even at that early stage. The Postgres Plus Advanced Server solution from EnterpriseDB that the company had in mind also gained favor with its Oracle-compatible layer, guaranteeing a reduction in the costs of migration. In November 2011, the final decision, following a degree of pretuning, was made to migrate from the increasingly costly Oracle solution to Postgres Plus Advanced Server with accompanying professional EnterpriseDB training opportunities.

Selection of Postgres Plus Advanced Server
The decision to implement the cost-saving open source based Postgres Plus Advanced Server from EnterpriseDB was supported by high vertical scalability on multi-core machines as well as reliable and stable Postgres performance on hardware with up to 64 cores. The solution runs on Linux 32-bit/64-bit platforms and on Windows 32-bit/64-bit platforms; HP-UX also runs on Itanium or Solaris. An additional benefit is that, thanks to the vastly simplified Oracle migration, companies can continue to benefit from investments made in Oracle after migrating to Postgres. The EnterpriseDB solution with its extensive functionality is also considered by far the most secure of the open source-based databases available. The system's ease of use also becomes evident in practice: Gallinat-Service's migration to Postgres required virtually no technical support from the EnterpriseDB support team and was completed independently for the most part.

User-friendly migration processes
Frank Ebinger described employees' feelings in the face of the migration decision: "Naturally, we had a healthy respect for the decision to switch our database structure definitively – anyone familiar with databases knows that these processes do not always run smoothly. But now that is done, it can be said that the migration really came off astonishingly easily. With the training options made available to us by EnterpriseDB, we were able to adjust to the new software under optimal conditions and to be perfectly prepared for the conversion in advance."

Well-documented PostgreSQL environment
The Gallinat-Service IT team first built a parallel Postgres environment for the migrated system so that any problems with the migration could be identified and, where necessary, resolved in advance. During this six-month Postgres proof of concept, the new database application ran in parallel to the Oracle application for three months following installation and initial implementation. A test suite ran nightly checks to ensure the Oracle and EnterpriseDB test screens matched. Gallinat-Service used the EnterpriseDB migration tool kit for the actual migration. Said Ebinger: "We did not have to call on EnterpriseDB support at all during the entire migration phase – all the details were already documented perfectly in the Postgres environment so that we were able to solve the problems that arose in the test run ourselves."

An example of one of the specific technical points that the Gallinat-Service IT team had to resolve during the migration to Postgres was the fact that the Postgres application does not have the standard NVL function available in Oracle – Postgres uses the COALESCE function instead. The SQL insert for partitioned tables is handled differently in Postgres Plus Advanced Server, as it uses Hibernate. The development team had already noticed this so it was possible to avoid potential logic errors in the application linked to the use of Hibernate. Another difference between the two database management systems is in the way the number of days is calculated – the team had to enter a differentiation in the source code in order to maintain the application's compatibility with Oracle. There were other differences which had to be taken into account during the migration with respect to Boolean table fields which Oracle maps using the "numeric(1)" data type but which Postgres maps using the "boolean" data type. There was no automatic support for the migration of boolean table fields so the migration had to be carried out using a temporary migration table. Moreover, in the event that table fields contain the numerical value 0, unlike Oracle, Postgres returns the value 0.00 instead of 0 via Hibernate. When querying the value 0, Gallinat-Service does not, therefore, use the value.equals(BigDecimal.ZERO) comparison (which would fail in this case) in the Java programming language but rather the comparison value.signum() == 0 in order to avoid potential logic errors.

In addition to the EnterpriseDB migration tool kit used for the migration, Gallinat-Service was also able to gain experience with the professional tools, Postgres Enterprise Manager and SQL Profiler, developed by EnterpriseDB, which ensure that databases are managed efficiently in the future. The company's experience with Postgres has been highly satisfactory to date: the cost situation has improved considerably and Gallinat-Service is now once again in a position to reliably calculate its future database investments. Said Ebinger: "After more than a year of using our definitive Postgres application, we are really very pleased. The performance of Postgres is stable and reliable. We have not had to compromise on speed or performance and are even considering using Postgres more widely in the future, perhaps extending it to the xDB replication server. Across the group as a whole, there is a clear trend developing at the ALBIS Leasing Group - to continue the implementation of alternative open source software solutions not only with regard to databases but in other applications as well."