Cypher query to get shortest path between A and B that doesn't go through C, that isn't massively slow? Or recommend alternative to Cypher/Neo4j -

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i'm working graph has thousands of nodes. have person nodes, , friends relationships between them. e.g., gus-[:friends]-skylar

if wanted find shortest friend path between hank , gus long they're not separated more 20 rels, this:

start hank=node(68), gus=node(66)  match p = shortestpath((hank)-[:friends*..20]-(gus))  return p

this works , fast, when found shortest path of length 10 or more.

but wanted find path hank gus does not go through glenn?

the query i've tried this:

start hank=node(68), gus=node(66), glenn=node(59) match p =(hank)-[:friends*..20]-(gus) not glenn in nodes(p) return p order length(p) limit 1;

this works on small graphs (30 or people), if there 1000's...the jvm runs out of heapspace.

so i'm guessing cypher finds all paths between gus , hank of length 20 or less, , applies filter? it's clear why slow.

in abstract sense, algorithm should doable same big o runtime, because change check make sure each node (as search) isn't 1 want avoid.

any suggestions how accomplish this? i'm pretty new cypher.

if not possible cypher, can recommend other database , graph language "stack"?

thanks

can test performance of following query? main difference compares paths instead of nodes. i've added direction in paths well, speed query.

start hank=node(68), gus=node(66), glenn=node(59) match p = allshortestpaths((hank)-[:friends]->(gus)) collect(p) guspaths, hank, glenn match p2 = allshortestpaths((hank)-[:friends]->(glenn)) collect(p2) glennpaths, guspaths filter(x in guspaths              none (x2 in glennpaths                          x = x2)) filtered return filtered order length(filtered) limit 1

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