group: support reference vector via deep accessor

[naoa]

No description provided.

[kou]

Should we pass NULL instead of key when key isn't an accessor?

[kou]

Can we simplify this?

e.g.:

      grn_accessor *a;
      for (a = (grn_accessor *)key;
           a->action == GRN_ACCESSOR_GET_KEY && a->next;
           a = a->next) {
        /* do nothing */
      }
      if (a->next &&
          a->next->action == GRN_ACCESSOR_GET_COLUMN_VALUE &&
          a->next->obj &&
          !a->next->next) {
        real_key = a->next->obj;
        data.need_resolved_id = true;
      }

[naoa]

If writing the loop to advance the grn_accessor first, I needed to change the following.

      for (a = (grn_accessor *)accessor;
           a->action == GRN_ACCESSOR_GET_KEY && a->next;
           a = a->next) {
        /* do nothing */
      }
      if (a &&
          a->action == GRN_ACCESSOR_GET_COLUMN_VALUE &&
          a->obj &&
          !a->next) {
        real_key = a->obj;
        data.need_resolved_id = true;
      }

Unlike the before changed condition, it will resolve id even if the first grn_accessor is GRN_ACCESSOR_GET_COLUMN_VALUE, is it ok?(I guess there are no case)

[kou]

Yes. grn_obj_column() returns a column itself not an accessor for the column with a column name of a table.

[naoa]

Thanks.
If so, I think it would be easier to understand if it advance the grn_accessor first.

[kou]

This may be slow for no deep case. Can you measure this with no deep case? (I hope that we have continuous benchmark mechanism...)

[naoa]

I see.
I will try the benchmark later.

[kou]

Thanks!
If this decreases performance, we can use the current logic only for no deep case.

[naoa]

I benchmarked with a drilldown of 3,144,060 reference vectors of results that no deep case.
There is a slight speed degradation.
I changed to switch them depends to the depth of the accessor.

Case 1. Use grn_accessor_resolve_id
8.912397623062134 sec
7.918306112289429 sec
7.794296026229858 sec
7.789118528366089 sec
7.804325819015503 sec

Case 2. Use grn_table_cursor_get key
8.694790124893188 sec
7.541107654571533 sec
7.652536869049072 sec
7.514059543609619 sec
7.609168767929077 sec

Case 3. Switch grn_table_cursor_get/grn_accessor_resolve_id depends to the depth of the accessor.
8.73039174079895 sec
7.665851831436157 sec
7.721802234649658 sec
7.707949638366699 sec
7.606190919876099 sec

[kou]

Thanks!