design flink cep pattern for transaction life cycle

[shishal singh <sh...@gmail.com>]

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<https://stackoverflow.com/questions/49273875/design-flink-cep-pattern-for-transaction#>

I have a scenario where I need to detect following pattern for a
transaction.

My basic transaction event look like this => *Transaction(id,status, time)*

Transaction goes through following state.

BEGIN -> COMPLETE (within 5 day, if this comes then no need to wait
for PROCESSING)
BEGIN -> PROCESSING (within 1 day)
PROCESSING -> PROCESSING (within 1 day, could happen upto 5 days)
PROCESSING -> COMPLETE (within 1 day)

In plain text, basically when a transaction is initiated it can go from
BEGIN to COMPLETE in 5 days. But If its can not be completed within 1 day
then it keep sending a PROCESSING event on that day. So this can happen
upto 5 day and then finally it can send COMPLETE event.

I want to alert if there is any diversion form this pattern.

The number of transaction in a day could be 10-50 million. I am evaluating
FlinkCEP for this problem. I have gone through their doc
https://ci.apache.org/projects/flink/flink-docs-release-1.4/dev/libs/cep.html

 Is it possible to design this pattern using Flink CEP?

Also if I am not wrong , I need to use PatternTimeoutFunction to trigger
alert.

Regards,
Shishal