== Lojas KD - SAP B1 Hacked Integration + Multibranch mode ==
Grab some coffee. This will be long, 2 parts, story.
--==] Part 0x01 [==--
When I started at Lojas KD, the e-commerce was running on a server from a
local vendor. I'm not even sure if it was a shared server, but for
restarting a server, we need to phone the support and give precise
instructions to the fellow guys... You got the picture. One of the first
moves was to migrate this proprietary e-commerce platform to a cloud-based
service (read AWS), so we would get some control over it.
On the other hand, the physical operation had recently implemented SAP
Business One, and had one on premise integration solution that read from an
integration table on e-commerce database and write to SAP.
We migrated the e-commerce platform to cloud, not without some turbulence,
but we made it. And a few weeks on a sunny afternoon... The orders started
entering SAP to the wrong customers. No recent deploy. Nothing that could
justify that behavior at first...
On the day after, the problem was still there. My manager called the SAP
Consulting firm that sold and implemented it. The closest schedule they had
was 3 weeks ahead, and we knew we would be broken by that time. In this
meantime, we noticed that new user ids were incrementing by some large
random amounts. I found the solution that worked passed 9:00 PM. It was a
very version specific bug on the autoincrement lock algorithm on MySQL.
A quick parenthesis here. The on premise integration solution that was
implemented wasn't a good one since ever. The infrastructure guys had to
restart it 5 or 6 times a day. It usually crashed the server, and took 99%
processing from one core all the time.
Well, after solving the MySQL autoincrement issue I asked my manager to see
the integration process...
- Davis, we do not have the code. It is just an executable file that keeps
running.
- OK, can I get a copy of it?
- What are you talking about? Are you thinking on reverse engineer that?
- Yes! I'm willing to disassembly and reverse engineer that.
- But Davis, you are just a PHP programmer.
- Can I get a copy, please?
In a mix of disbelief, perplexity about my unknown skills and despair about
the lack of a better solution, I got a copy of the .exe file. One hour later
I get some readable code.
Another guy on the team promptly recognized the code as C#... A few minutes
later, we found two villains on the code. The integrator was truncating the
ID to 6 digits only, so when the autoincrement went over the number 1
million, we start to see the problems. And everything was running inside a
while (true) block.
Fix, compile, deploy. Voila! Up and running again. But we knew some day we
would need to refactor that integration entirely.
--==] Part 0x02 [==--
One of the major business changes we enabled at Lojas KD was the logistic
model change. It operated as a cross docking but in a continental country
as Brazil, this implied into a lot of inefficiency on products
transportation and all related costs.
A product produced near a customer need to travel 3-5 days to our dock. And
wait for a few days, until another 3-5 days back to customer house.
A better solution to our case was changing it to drop shipping, ie, the
product would leave the factory directly to customer's house.
But this required a lot of changes, starting by enabling the multi-branch
mode on SAP B1, as well as the integration piece must know to which
branch(es) a given order should enter. The other part was to change our
product listing to reinforce a location-based purchase, thus reducing the
costs - this was made on the e-commerce database as well as on Apache Solr
search engine that used to power our pages.
--==] Aftermath [==--
It wasn't a short task, but it was a very grateful experience. I worked
together with our DBA, which was also a senior C# developer. We pair
programmed. I learned C# and a lot of neat tricks. We built some really nice
pieces of software. And this saved basically a year of operation in costs
reduction.