arangosh> db._profileQuery(`
........> LET list = (FOR doc in acollection FILTER doc.value > 90 RETURN doc)
........> FOR a IN list 
........>  FILTER a.value < 91 
........>  RETURN a`, {}, {colors: false, optimizer:{rules:["-all"]}}
........> );
Query String (116 chars, cacheable: false):
 LET list = (FOR doc in acollection FILTER doc.value > 90 RETURN doc)
 FOR a IN list 
  FILTER a.value < 91 
  RETURN a

Execution plan:
 Id   NodeType                  Calls   Items   Runtime [s]   Comment
  1   SingletonNode                 1       1       0.00000   * ROOT
  7   SubqueryNode                  1       1       0.01107     - LET list = ...   /* const subquery */
  2   SingletonNode                 1       1       0.00000       * ROOT
  3   EnumerateCollectionNode      10   10000       0.00330         - FOR doc IN acollection   /* full collection scan */
  4   CalculationNode              10   10000       0.00257           - LET #5 = (doc.`value` > 90)   /* simple expression */   /* collections used: doc : acollection */
  5   FilterNode                   10    9909       0.00307           - FILTER #5
  6   ReturnNode                   10    9909       0.00210           - RETURN doc
  8   EnumerateListNode            10    9909       0.00182     - FOR a IN list   /* list iteration */
  9   CalculationNode              10    9909       0.00254       - LET #7 = (a.`value` < 91)   /* simple expression */
 10   FilterNode                    1       0       0.00135       - FILTER #7
 11   ReturnNode                    1       0       0.00000       - RETURN a

Indexes used:
 none

Optimization rules applied:
 none

Query Statistics:
 Writes Exec   Writes Ign   Scan Full   Scan Index   Filtered   Exec Time [s]
           0            0       10000            0      10000         0.01873

Query Profile:
 Query Stage           Duration [s]
 initializing               0.00001
 parsing                    0.00005
 optimizing ast             0.00001
 loading collections        0.00001
 instantiating plan         0.00002
 optimizing plan            0.00011
 executing                  0.01679
 finalizing                 0.00171