Running Neo4j purely in memory without any persistence

Question

I don't want to persist any data but still want to use Neo4j for it's graph traversal and algorithm capabilities. In an embedded database, I've configured cache_type = strong and after all the writes I set the transaction to failure. But my write speeds (node, relationship creation speeds) are a slow and this is becoming a big bottleneck in my process.

So, the question is, can Neo4j be run without any persistence aspects to it at all and just as a pure API? I tried others like JGraphT but those don't have traversal mechanisms like the ones Neo4j provides.

Elisha

Did you find a feasible solution yet? – Transferor

so Neo4j does not support this? I also would like to run Neo4j in memory, without any backup in the file system, just for its graph traversing capabilities. – Gules

Answer 1

As far as I know, Neo4J data storage and Lucene indexes are always written to files. On Linux, at least, you could set up a ramfs filing system to hold the files in-memory.

See also:

• Loading all Neo4J db to RAM

Mesolithic

<quote> we are planning to do an in-memory implementation of Neo4j, but first after 1.0, simply no bandwidth right now :( </quote> I'm using 1.8 and don't see in memory support in the docs anywhere. – Elisha

Yep, I guess nobody found that bandwidth yet ;-) – Mesolithic

Also, you could try ImpermanentGraphDatabase for testing? github.com/neo4j/community/blob/master/kernel/src/test/java/org/… – Inconspicuous

Answer 2

How many changes do you group in each transaction? You should try to group up to thousands of changes in each transaction since committing a transaction forces the logical log to disk.

However, in your case you could instead begin your transactions with:

db.tx().unforced().begin();

Instead of:

db.beginTx();

Which makes that transaction not wait for the logical log to force to disk and makes small transactions much faster, but a power outage could have you lose the last couple of seconds of data potentially.

The tx() method sits on GraphDatabaseAPI, which for example EmbeddedGraphDatabase implements.

Gerry

I switched over to the batch inserter now, slight improvement but not a lot. So no transactions to worry about. – Elisha

Answer 3

you can try a virtual drive. It would make neo4j persist to the drive, but it would all happen in memory https://thelinuxexperiment.com/create-a-virtual-hard-drive-volume-within-a-file-in-linux/

Corollary