So how graph is maintained ? Is there any document to read for it, I am just trying to understand

how is the data stored?

I can see Postgresql tables and data stored in it, I am trying to understand where the graph data stored which is traversed to compute permission checks.

the graph structure is stored in the namespace table

Got it, thanks for sharing, as dispatcher sends smaller query on different node to traverse the graph, I made assumption , graphs are maintained in memory.

the structure is cached in memory

I see, I guess only part of structure can be cached, as in many cases structure can be big enough to fit in size of memory.

more or less