Day 83 - Data Loaded into DB2 on Windows

We have finally received the database data from OS/390 in a format that we were able to load it without trouble in DB2 on Windows.

Some of the weird problems we got on AS/400 will no longer bother us but now, we have to rewrite some scripts because DB2 in Windows is different from DB2 on AS/400.

One of the problems was that I an insert into script that loads the postal code with almost 300000 records. I had to loaded it through the DB2 command line tool. Here's how one can do it:

1. Open the DB2 Command Line Processor tool. Don' t just open a regular shell since it will not work, some environment settings are required.
2. In the shell, execute the following commands:
   

db2 connect to {database} user {username} using {password}
db2 -vf {path/script.sql} -t > output.txt

Don't forget to have a tail and grep installed, if you wish to track the evolution of the script execution and check for operation success.

The entire process took about 6 hours, this includes taking the data from OS/390, moving it to Windows, load it into DB2 in Windows and preparing the staging area with look up and convert tables. Way to much time. This process will definitely be optimized.

We've also found out one of the most idiotic functionality in software I've ever seen.
After installing the database client on the local machines, and after configuring the server access, the Command Editor only allows one to open files from the database server computer. Yes, I mean it is impossible to open any local file using the Command Editor. And no, that is not configurable!

Day 30 - Performace Tests

There's a set of performance tests to do before choosing the final migration infrastructure.

There's tests over the initial data extraction from OS/390 and loading into AS/400.

There's tests over the data transformation rules.

There's tests over the final data loading into GIS.

From this set of tests, only ours, the data transformation rules, have been performed so far.

As expected, AS/400 is not a fast machine to run Data Fusion transformation engine. We already knew this, but AS/400 system administrators always say we're wrong and that they have a fantastic and fast machine. Their pride has been hurt...

As an example, running entirely in AS/400, 400000 source records have migrated at ~800 records per secord. Note that this was a local data migration execution, the source and target databases are on the same machine as the transformation engine.

But running the same transformation engine on my, not very fast, desktop computer with 1GB of RAM, the same 400000 records migrated at ~1400 records per second. Note that on this test the source data was retrieved from AS/400, transformed on my desktop compute, and sent back to AS/400, i.e. the data had to travel over a common 100 Mbit network.

The protocol loading interface was also subject to tests and it's CPU bounded, We have one single processor, of a 4 processor machine, and it consumes 100% of that CPU. When running on AS/400, it perfomed ~12000 records per second. Running on the desktop it does only ~8000 records per second.

The scalability tests on AS/400, with a single CPU for us, proved that a linear execution is faster than a two parallel executions. We haven't had the chance to test parallel execution with more CPUs.

We've been discussing what was the best approach allow us to scale and one thing is for sure, we need to run the transformation engine outside the AS/400, because on the D day we have to share, as it's happening now, the machine with others, specifically with GIS data loading.

Probably we'll have a 6 or 8 CPU machine running Linux and connected to AS/400 over a 1 Gbit network. This will allow us to run multiple transformation engines and free AS/400 for the other data migration processes.

Day 3 - Target specification

The target specification arrived today.
It's an hierarchical structure that will result in a flat file where each line will represent a specific piace of information, identified by a code.
We've started to work on it, but since the specification is more like a meta-model, we had to make some adjustments to comply with such a dynamic structure.
All problems have been solved, they were actually simple decisions that the source team helped to make.
The DB2 model has been created and our scripts turned it into mapping sheets, that will be used in the functional mapping performed by the source and the target teams.

A piece of the source data has become available. It has been extracted from the OS/390 in EBCDIC and in text formats in order to allow some AS/400 loading tests.
The data looks correct, but each row has been loaded as a single record, the copybook rules have not been applied and therefor, it will have to be loaded again. Nevertheless, the fact that the information looks correct is a good enough as the result of the first try.

The first workstation also arrived today, allowing us to install and configure some of the software required for the data migration, and allowing us to access to the development AS/400 machine.

It will not depend on us, but if next week things work out the way we've planed, we'll be able to recover the one day delay.

Day 1 - Kick off

The project has been officially kicked off.

There was the traditional meeting where all teams where present and an overview of the project was presented. All teams involved have previous data migration experience, which is good.

The project should be completed around mid October, but I felt that management confidence to comply with the date is not very high. This is not a bad signal as one might think, since management showed that it is aware of some real difficulties. Those difficulties may become technical challenges and may delay the project.
Nevertheless, I do believe that the original due date can be achieved.

There will be two phases. The first phase, the current one, will use a small entity subset in order to test the performance of the ETL and to tune the process.
The second phase will be the continuity of the previous phase, but now including all applications and entities.


The project itself consists of migrating the current insurance application, running on OS/390 mainframe, into the new system, the GIS Non-Life, running on AS/400, all using DB2, SAM and VSAM.
There are some other satellite applications running on SQL Server 2005 on Windows.
The ETL tool will be Data Fusion and it will run on AS/400 under the Qshell.

The ETL process will be implemented in a slightly different way from the usual scenario. Usually the data is extracted from the source database and loaded into the target database. This is not the case in this project.
Eventually, the data will be loaded into the final target database, but there's an intermediate step. The ETL process performed by Data Fusion will deliver the data on flat files that will be later consumed by the GIS loader. The GIS loader will validate and load the data into the final database.

Since our (ETL team) experience tells us that performance on AS/400 may be a problem during the ETL process, there was some discussion over the performance tests to be performed during phase one.

If the performance becomes an issue, the data migration may have to be incremental, instead of one-shot. This will be a problem because the source team cannot identify which data has been changed and needs to be migrated again to refresh the target system. One challenge that has been given to us, is to think in a fast way to identify if a record has changed and needs to be migrated again, just in case of a B plan is required.