Node disk storage problem apoc.refactor.mergeNodes (disk store size do not decrease but increase)

[Peter_Lian]

Suppose I have 100,000 nodes with 10 properties which cost about 100MB to storage on Neo4j, i.e., the following file

However, suppose there're 10% duplicate node (10,000), after using apoc.refactor.mergeNodes only 90,000 nodes remain. I thought that the disk storage would decreased since I just merge the duplicate node, but to my surprised it was not but even increased a little (about 0.1MB)

Problem : Why disk storage increase but not decrease after merging the duplicate node via apoc.refactor.mergeNodes? and how to solve this problem (I got the disk-storage problem...)

Thanks.

[dana_canzano]

@Peter_Lian 

Version of Neo4j?

why did disk space grow?   see https://neo4j.com/developer/kb/understanding-database-growth/

how to address.  Run `neo4j-admin copy`