> Even if you nail down the problem to exactly one representation, they still don't fit.
This is exactly the problem I've found with graph databases. I've never successfully used a graph database to solve a problem, and multiple other engineers I've spoken to have bounced off them in a similar way. The problem is I don't have an arbitrary graph problem, mine is specific, and as you say the choices a graph database makes matter. It really gives me greater appreciation for the relational model because so many things can be made to work on a relational database. It may not be elegant, but it works.
I think the way I'd like to approach graphs, if I do it again, would be to use a graph represented as sparse matrices in memory as an index. This is more or less in line with what you get from expressing the graph problem in application code, but maybe easier to understand and maintain? I guess that is to say I'm still optimistic there might be some general purpose solution like RedisGraph (now FalkorDB) that makes sense to use this way, but I'm not sure I'd try to use an out-of-core graph database again.
This is exactly the problem I've found with graph databases. I've never successfully used a graph database to solve a problem, and multiple other engineers I've spoken to have bounced off them in a similar way. The problem is I don't have an arbitrary graph problem, mine is specific, and as you say the choices a graph database makes matter. It really gives me greater appreciation for the relational model because so many things can be made to work on a relational database. It may not be elegant, but it works.
I think the way I'd like to approach graphs, if I do it again, would be to use a graph represented as sparse matrices in memory as an index. This is more or less in line with what you get from expressing the graph problem in application code, but maybe easier to understand and maintain? I guess that is to say I'm still optimistic there might be some general purpose solution like RedisGraph (now FalkorDB) that makes sense to use this way, but I'm not sure I'd try to use an out-of-core graph database again.