Review count() implementation - consider FT.AGGREGATE

[abrookins]

Summary

The current FindQuery.count() implementation uses FT.SEARCH with LIMIT 0 0 and nocontent=True:

async def count(self):
    query = self.copy(offset=0, limit=0, nocontent=True)
    result = await query.execute(exhaust_results=True, return_raw_result=True)
    return result[0]

This works, but FT.AGGREGATE with a count reducer may be a better approach.

Why FT.AGGREGATE might be better

1. Purpose-built for aggregations - FT.AGGREGATE is designed for operations like counting, grouping, etc.
2. More flexible - Could support count() with grouping (e.g., count by category)
3. Potentially more efficient - Aggregation pipeline is optimized for this use case

Example with FT.AGGREGATE

FT.AGGREGATE idx * GROUPBY 0 REDUCE COUNT 0 AS total

This returns just the count without any document data.

Tasks

• Benchmark current FT.SEARCH LIMIT 0 0 vs FT.AGGREGATE for count
• Evaluate if FT.AGGREGATE provides any performance benefits
• Consider adding grouped count support (e.g., Model.find().count(group_by="category"))

[abrookins]

PR #313 also implemented count() using FT.AGGREGATE, though with a more complex approach using matched_terms(). That PR has been closed due to staleness but is worth referencing here for the FT.AGGREGATE approach.