The issue was caused when the optimiser decided to use an index on an attribute, but the attribute access was contained in a logical OR as follows:
FILTER (c.<indexed-column> == <value> || c.<some-other-column> == c.<indexed-column>)
In this case, the index on <indexed-column> was accessed with the constant <value>, but the right-hand side of the OR was ignored, leading to possibly incomplete results
This change will create field access hints also for AQL function calls.
Calls to functions will not be optimised, but meaningless usages of functions will not be optimised away.
For example:
FOR p IN PATHS(users, relations, "outbound")
FILTER LENGTH(p.edges) > 0 && LENGTH(p.edges) < 0
RETURN p
The FILTER in the above query uses the LENGTH() function two times in a way that no result will be produced.
Before, function calls were excluded from expression collapsing and simplification.
Now, multiple calls to the same function with the same call argument might be optimised away if the calls will
lead to no results being produced. This will only work for functions that are called with exactly one argument
which also must be an attribute name, and when the function calls are used in relational operations.
Jan Steemann
Frank Celler