My question is on the NOTE under 'Using MATCH to retrieve nodes' (Link in topic)
It says, if we specify 'Node LABEL' for the 'MATCH', the graph engine uses an index to retrieve the nodes which will perform better than not using a label for the 'MATCH', however, the Neo4j Database is Index-free adjacency, isn't it? If so please explain what indexes are we talking about here?
Hello Neelkanth and welcome to our Community!
Index-free adjacency means that Neo4j stores nodes and relationships as direct pointers in the graph. Unlike in a relational database, you need to go to a separate table to connect parts of the database (joins). Neo4j certainly does use indexes like that, but the indexes used (the default one for node labels) are all memory-resident and you need not worry about creating them. Later in this course you will learn about the different types of indexes that you can create for your graph to enhance performance.