Depending on what you use the field for, you can use BinaryDocValuesField
which encodes a byte[] and lets you store the data however you want. But
how are you using these fields later at search time?
On Tue, Jun 28, 2022 at 3:46 PM linfeng lu <linfeng...@hotmail.com> wrote:
> Hi~
>
> We are trying to build an OLAP database based on lucene, and we heavily
> use lucene's *DocValues* (as our column store).
>
> *We try to use DocValues to store the array type field. *For example, if
> we want to store the *field1* and *feild2* in this json document into
> *DocValues* respectively, SORTED_NUMERIC and SORTED_SET seem to be our
> only option.
>
> *{*
> * "field1": [ 3, 1, 1, 2 ], *
> * "field2": [ "c", "a", "a", "b" ] *
> *}*
>
>
> When we store *field1* in SORTED_NUMERIC and *field2* in SORTED_SET, we
> will get this result:
>
> *[image: Community Verified icon]*
>
> field1:
>
> - origin: [3, 1, 1, 2]
> - in SORTED_NUMERIC: [1, 1, 2, 3]
>
> field2：
>
> - origin: [”c”, “a”, “a”, “b” ]
> - in SORTED_SET: ords [0, 1, 2] terms [”a”, “b”, “c”]
>
>
> The original ordering relationship of the elements in the array is lost.
>
> We're guessing that lucene's DocValues are designed primarily for sorting
> and aggregation, so the original order of elements may not matter.
>
> But in our usage scene, it is important to keep the original order of the
> elements in the array (we allow user to access the elements in the array
> using the subscript operator).
>
> We wonder if lucene has plans to add new types of DocValues that can store
> arrays and keep the original order of elements in the array?
>
> Thanks!
>
