Reuse doc values

[anacrolix]

Reduces allocations by 75% for a single sort field.

Before:

After:

[mschoch]

This looks good to me.

As I understand it, the allocations we avoid are here:

• https://github.com/blugelabs/bluge/blob/master/search/search.go#L112
• https://github.com/blugelabs/bluge/blob/master/search/search.go#L114

And the usage pattern is already one where we expect the same fields.

Can you share what the workload is that you used to generate the profiles? Would it be appropriate as a benchmark in the package?

[anacrolix]

That's right. The workload is an index with a text field and a numeric field. I'm doing a top N search, matching on the text field and sorting on the numeric field. I don't think it matters but the query has MatchQueryOperatorAnd.