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I want to setup dynamodb in a way that I can query for events that fall in X radius using geohashes and then sort it by the startDateTime.

The problem with BatchGetItem is that I can query multiple partition keys (geohash) at same time but cannot sort them, unless I have misunderstood the limitations of BatchGetItem.

Eg. I am standing in the top left/right corner of the geohash (abcde) and want to search for the events that falls under 10KM radius which would require querying multiple partition keys (abcde,abcdx,abcdy) and would like to sort them all by the startDateTime which is the sort/range key.

Global Secondary Index: Partition key - Geohash Sort key - StartDateTime

App stack: nodejs, dynamodb

Tried to make use of dynamodb-geo library but cannot understand how would sorting work even if I use that.

Danish Khakwani
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1 Answers1

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You are right, you can't use sort key in batch get item. Here are a few of my thoughts:

  1. Move to another database with geo spatial index support and without the limitations of DynamoDB.
  2. Query multiple partition keys in parralel with sort key.
  3. Make an index/aggregate table to query before, so you can filter out irrelevant partition keys.
  4. Create a new table where key is multiple consecutive partition keys(geo hashes), depends on your usage, might have to deduplicate the data which will add complexity.

You know your access patterns, so you can think about speed and cost optimizations.

KafKafOwn
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