ArangoDB query slows down exponentially with depth - Stack Overflow

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We are testing a very large depth tree with ArangoDB. It's loaded up in docker using the latest arangodb-instance image.

A tree with 1,000,000 nodes and 1,000,000 edges has been uploaded. It is set up with one child per node. Showing this visually, a portion of the graph looks like this.

With this set up, the test is this query

  FOR v IN 1..100 INBOUND 'node/1_30000' GRAPH 'Line'
 RETURN 
    [v._key, v.parameter]

For 100 traversals, this is quite fast

Query Statistics:
 Writes Exec      Writes Ign      Doc. Lookups      Scan Full      Scan Index      Cache Hits/Misses      Filtered      Peak Mem [b]      Exec Time [s]
           0               0                 0              0             200                100 / 0             0             32768            0.00163

When this is expanded by 100x (FOR v IN 1..10000), the query exec time grows by 190,793 times (from 0.00163s to 310.99316s).

 Query Statistics:
 Writes Exec      Writes Ign      Doc. Lookups      Scan Full      Scan Index      Cache Hits/Misses      Filtered      Peak Mem [b]      Exec Time [s]
           0               0                 0              0           20000              0 / 10000             0           1572864          310.99316

In looking at the timings, the time is almost exclusively in TraversalNode

 2   TraversalNode        10     9   10000          0     310.99188    

In this exercise to see where a graph database can be effectively utilized it appears as if this case isn't one of them.

Is a large depth tree not a tuned use case for ArangoDB or are there ways this tree should be tweaked/queried that are not set by default? Can any graph database handle this use case without exponentially slowing down?

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