Do recommendation systems which give suggestions happen behind using realtime or batch ?

[Monica Shiralkar]

On the internet if we search for say some tourist places.Next time when we come back we would automatically start seeing suggestions on the hotels in that city and trip plans for that city. I am not sure what happens behind the scenes but I think the huge data must be getting gathered and analyzed and then generating recommendation for that user.Behind the scenes do these work on realtime mode or using batch mode ?
Thanks

[Les Morgan]

Monica,

Both, and it depends on the advertisements you are getting.  You may have noticed that you browse a website and moments later, literally seconds, you are into facebook and there are related advertisements waiting in your feed.  That is real time, or pseudo real time, processing and data collection.  You then have the skimmed information shared across a network of business partners that begin spamming you within days--that is batch processed.

Les

[Monica Shiralkar]

Thanks. For batch do they use hadoop clusters ? For streaming do they use Spark/Strom/Flink ? Is all this raw data stored in a NoSQL like Hbase/Cassandra/mongoDB.

[Les Morgan]

Monica,

I do not know, but the last time I checked, and it's been about a decade, Amazon was using a modified Oracle product.

Les

[Monica Shiralkar]

Thanks