arangosh> db._profileQuery(`
........> FOR u IN myusers
........>  COLLECT ageGroup = FLOOR(u.age / 10) * 10
........>  AGGREGATE minAge = MIN(u.age), maxAge = MAX(u.age), len = LENGTH(u)
........>  RETURN {
........>    ageGroup, 
........>    minAge, 
........>    maxAge,
........>    len
........>  }`, {}, {colors: false}
........> );
Query String:
 FOR u IN myusers
  COLLECT ageGroup = FLOOR(u.age / 10) * 10
  AGGREGATE minAge = MIN(u.age), maxAge = MAX(u.age), len = LENGTH(u)
  RETURN {
    ageGroup, 
    minAge, 
    maxAge,
    len
  }

Execution plan:
 Id   NodeType                  Calls   Items   Runtime [s]   Comment
  1   SingletonNode                 1       1       0.00000   * ROOT
  2   EnumerateCollectionNode       1      20       0.00001     - FOR u IN myusers   /* full collection scan */
  3   CalculationNode               1      20       0.00001       - LET #5 = (FLOOR((u.`age` / 10)) * 10)   /* simple expression */   /* collections used: u : myusers */
  4   CalculationNode               1      20       0.00000       - LET #7 = u.`age`   /* attribute expression */   /* collections used: u : myusers */
  6   CollectNode                   1       8       0.00002       - COLLECT ageGroup = #5 AGGREGATE minAge = MIN(#7), maxAge = MAX(#7), len = LENGTH(u)   /* hash */
  9   SortNode                      1       8       0.00001       - SORT ageGroup ASC
  7   CalculationNode               1       8       0.00001       - LET #11 = { "ageGroup" : ageGroup, "minAge" : minAge, "maxAge" : maxAge, "len" : len }   /* simple expression */
  8   ReturnNode                    1       8       0.00000       - RETURN #11

Indexes used:
 none

Optimization rules applied:
 Id   RuleName
  1   move-calculations-up
  2   remove-redundant-calculations
  3   remove-unnecessary-calculations
  4   move-calculations-up-2
  5   move-calculations-down

Query Statistics:
 Writes Exec   Writes Ign   Scan Full   Scan Index   Filtered   Exec Time [s]
           0            0          20            0          0         0.00056

Query Profile:
 Query Stage           Duration [s]
 initializing               0.00000
 parsing                    0.00007
 optimizing ast             0.00001
 loading collections        0.00000
 instantiating plan         0.00003
 optimizing plan            0.00026
 executing                  0.00008
 finalizing                 0.00010