NoSQL: Getting the latest values from tables DynamoDB/Azure Table Storage

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忘掉有多难
忘掉有多难 2020-12-08 00:39

I have a little problem that needs some suggestions:

  • Lets say we have a few hundred data tables with a few dozen million rows each.
  • Data tables are ti
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  •  鱼传尺愫
    2020-12-08 01:30

    I just published an article today with some common "recipes" about DynamoDB. One of them is "Storing article revisions, getting always the latest" I think it might interest you :)

    In a nutshell, you can get the latest item using Query(hash_key=..., ScanIndexForward=True, limit=1)

    But, this assumes you have a range_key_defined.

    With Scan, you have no such parameter as ScanIndexForward=false and anyway, you can not rely on the order as data is spread over partitions and the Scan request is then load balanced.

    To achieve you goal with DynamoDB, you may "split" your timestamp this way:

    1. hash_key: date
    2. range_key: time or full timestamp, as you prefer

    Then, you can use the 'trick' of Query + Limit=1 + ScanIndexForward=false

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