What's the correct way to remove old db and start a fresh one?

[Rogie]

I don't know what the correct way to start an empty db. I know that I can remove all nodes and relations by doing

match (n)  
with n limit 10000  
DETACH DELETE n;

over and over again until everything is gone, but this is not reasonable to do on a huge database.

Is there not a simpler way to remove everything?

[Cobra]

Hello @Rogie

With apoc:

CALL apoc.periodic.iterate('MATCH (n) RETURN n', 'DETACH DELETE n', {batchSize:1000, iterateList:true})

Regards,
Cobra

[Rogie]

Trying this now, but it seems extremely slow. Has been running for an hour and still not complete.

[Cobra]

How many nodes and relationships do you have?

Did you put index on them?

[Rogie]

Around 10 million nodes. Each type has a uniqueness constraint for some attribute.

[ofer_bar]

Why not simply create a new database?
Anyway, if you insist on deleting the objects don't forget to erase the indexes and constraints (schema). Just look up the command I don't remember the syntax.

[Cobra]

Do you have enough RAM and a good processor?

The request I gave you is the fastest one to delete everything in the database

Regards,
Cobra

[Rogie]

How long should I expect it to take? There are 8GiB of ram on the system.

[Cobra]

To be honest I don't know, 8Go looks small for a database with 10 millions nodes

You just need to wait

[Rogie]

How much RAM do you suggest to have in this case?

[Cobra]

I know there is hardware sizing but I never test it

[stugorf]

Hi @Rogie,

If you are using Neo4j 4.x you can switch to the system database using :use system and then run drop database <database_name> Then to create a new empty database run create database <database_name> .

[emigre459]

To be clear, this solution only works for Enterprise Edition.