KSQL consistency - apache-kafka

Question

I am doing a PoC using dotnet and ksql.
https://github.com/pablocastilla/kafkiano/
The overall idea is to see if I can implement business logic using KSQL. In the example I introduce devices in the stock and make orders from it. The example consists in this:
Two main streams:
Inventory stream receives the adding event to inventory.
Orders stream receives orders of products.
With those streams I create two tables:
ProductStock: it just adds the products to the stock
Orders: counts the orders by product
After those two tables I create another table with the difference between the orders and the products in the inventory, just to know if there are products left.
With a join in that last table and the order stream I can have the stock left when that order is processed.
I am introducing the events using the productname as key. So far it works well in my machine, but my questions are:
Is this consistent in a big production environment? I would like to know restrictions about when the consistency is broken when a lot of events are received in parallel.
How can I know which queries are executed before others? I need to count the difference between inventory and orders before the I join that difference with the order stream
Thanks
KSQL:
//INVENTORY STREAMS
CREATE STREAM InventoryEventsStream (ProductName VARCHAR, Quantity INT) WITH (kafka_topic='INVENTORYEVENTS', key='ProductName', value_format='json');
//TABLE GROUPING BY PRODUCT
CREATE TABLE ProductsStock as select ProductName,sum(Quantity) as Stock from InventoryEventsStream group by ProductName;
// ORDERS STREAMS
CREATE STREAM OrdersCreatedStream (ProductName VARCHAR,Quantity INT, OrderId VARCHAR, User VARCHAR) WITH (kafka_topic='ORDERSEVENTS', key='ProductName', value_format='json');
//TABLE GROUPING BY PRODUCT
CREATE TABLE ProductsOrdered as select ProductName as ProductName,sum(Quantity) as Orders from ORDERSCREATEDSTREAM group by ProductName;
// join with the difference
CREATE TABLE StockByProductTable AS SELECT ps.ProductName as ProductName,ps.Stock - op.Orders as Stock FROM PRODUCTSORDERED op JOIN ProductsStock ps ON op.ProductName = ps.ProductName;
//logic: I want the stock left when I make an order
SELECT ocs.OrderId,ocs.User,sbpt.Stock FROM OrdersCreatedStream ocs JOIN StockByProductTable sbpt ON sbpt.ProductName = ocs.ProductName;

Answer 1

I copy and paste the github answer I got from the confluent team:
"I get your question. A minimal answer for your question is, it executes as soon as your message is available in the stream.
A good analogy would be a machinery which is always running.
Whenever a payload enters inside, it will just process it. Now it comes to you on the chaining part. Are you inserting some payload to a new record stream after processing? Then yes, you can call it 'chaining'. Once you run / execute CTAS/ CSAS statements you see something like 'Table/Stream created and Running' , that is exactly what it means.
You have ignited an always running query!"