How to perform the Search operation when i have Thousands of Points

[Koteswara Siva Kumar Devineni]

I have geo location of vehicles and my point in the city and I need to find those vehicles that are within 5kms radius of my point.
I could represent the vehicle locations and my point with S2 cell id. But how can i query ?
Do I need to load data for all the Vehicle locations in memory and then use S2 library to find my target users.

Or can I store data for all the users in a database and make query on S2 cell ids.
As S2 cell id is using Hilbert curve, Can we know those vehicles which have closer S2 cell ids are closer in distance with each other.
Or is there any other method which i have to use here to perform the search operation?

Please suggest..

[Martin Phee]

I've been playing around with this myself.  If you have any thoughts I would be interested.

So for my simple solution, I did this in Go. 

var point = s.Point{Lat: 51.4622952, Lng: -0.1994539}
rc := &s2.RegionCoverer{MaxLevel: 20, MaxCells: 10}
covering := s.S2CellIdsCoveringGivenRadius(500, point, rc)
for _, c := range covering {
   queryRedis(c)
}

pipeline := redisRepo.Pipeline()
var results []*redis.StringSliceCmd
for _, c := range covering {
   results = append(results, createQuery(c, pipeline))
}

cmds, err := pipeline.Exec()
if err != nil {
   panic(err)
}
func createQuery(c s2.CellID, pipeline redis.Pipeliner) *redis.StringSliceCmd {
   // perform a range lookup in the DB from bmin key to bmax key, cur is our DB cursor
   //var cell s2.CellID
   result := pipeline.ZRangeByScore("branches", redis.ZRangeBy{
      Min: strconv.FormatInt(int64(c.RangeMin()), 10),
      Max: strconv.FormatInt(int64(c.RangeMax()), 10),
   })
   if result.Err() != nil {
      panic(result.Err())
   }

   return result
}

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