List property ordering - mixed index not used as expected

Hi All,

Using JanusGraph 1.1.0, it seems that mixed index is not used when order().by() step is used for a property with LIST cardinality. I have tried both with Lucene and Elasticsearch index backends and with none of them the index was used for sorting.

For single cardinality

submissionDate4

submissionDate4

property, it seems that mixed index is utilized for sorting as seen on

single property - index used for ordering.png

single property - index used for ordering.png

enclosed.

When I created the same

submissionDate4

submissionDate4

property as list, the ordering is done by

OrderGlobalStep

OrderGlobalStep

as seen on

list property - index not used for ordering.png

list property - index not used for ordering.png

enclosed.

I have also enclosed how the graph and schema were created:

for single cardinality property see enclosed
```
single.groovy
```
```
single.groovy
```
for list cardinality property see enclosed
```
list.groovy
```
```
list.groovy
```

Could you please help pointing me to the right direction what I am doing wrong with the list property indexing?

Thank you.

single.groovy1.5KB

list.groovy1.72KB