I was working on blockchain project stellar, and setup a node. I had variety of database to select for my node including MySql, postgreySql, oracle, mongoDb, Cassandra, HBase etc.
blockchain stores same data to every node thus providing data immutability, better security, decentralized system, to name few.
I noticed while setting up node we can chose any database for our machine. How does blockchain maintain operations for so many different database type?
blockchain needs to insert new block details in every single node and also check for validation. How blockchain managed to do so many complex operation so fast when 2 nodes are not even in same database?
In Stellar, reliable synchronisation between nodes is the responsibility of the Stellar Consensus Protocol. The data store for each node is a mechanism for caching the state of the ledger, rather than a way to synchronise with other nodes.
This ten minute video provides a good introduction to SCP.
There is a dedicated Stellar StackExchange where you can ask further questions.