Performance difference between global and local accums

#1

Hey,

I would like to understand in-depth the working and performance differences between a local and global accum. Also, how this changes as we scale the graph.

For Example, We have 10K vertices
Vertex A(id, a1 String, a2 String) - Vertex B(id String, b1 String, b2 String)

  1. We have a global mapaccum<String, String> @@v_store,
    Key = vertex-ID, value - vertex attribute.
SELECT a FROM Vertex_A:a - ()- Vertex_B:b
@@v_store += (a.d -> b.b1);

2) Local accum @b_attr
SELECT a FROM Vertex_A:a - ()- Vertex_B:b
a.@b_attr += b.b1;

Usage:

SELECT a FROM Vertex_A:a - ()- Vertex_B:b
ACCUM 
@@v_store .get(a.id)
...
...


SELECT a FROM Vertex_A:a
ACCUM
a.@b_attr
.,..
...

I would like to understand the performance of the write and read.
What would be the preferred scenario in terms of space/time complexity?