CODEWITHSUNDEEP
amazon-web-servicesamazon-dynamodb
Red Bottle
Red Bottle

Reputation: 3080

How to do "Select COUNT(*)" in DynamoDB from the AWS management console or any other 3rd party GUI?

Hi Im trying to query some table in DynamoDB. However from what I read I can only do it using some code or form the CLI. Is there a way to do complex queries from the GUI? I tried playing with it but can't seem to figure out how to do a simple COUNT(*). Please help.

Upvotes: 1

Views: 3406

Answers (1)

Gustavo Tavares
Gustavo Tavares

Reputation: 2805

  1. Go to DynamoDB Console;
  2. Select the table that you want to count
  3. Go to "overview" page/tab
  4. In table properties, click on Manage Live Count
  5. Click Start Scan

This will give you the count of items of the table at that moment. Just be warned that this count is eventually consistent; what means that if someone is performing changes in the table at that exact moment your end result will not be exact (but probably very close to reality).

Digressing a little bit (only in case you're new to DynamoDB):

DynamoDB is a NoSQL database. It doesn't support the same commands that are common in SQL databases. Mainly because it doesn't support the same consistency model provided by SQL databases.

In SQL databases, when you send a count(*) query your RDMS make some very educated guesses and take some short paths to discover the number of lines in the table. It does that because reading your entire table to give you this answer would take too much time.

DynamoDB doesn't have means to make these educated guesses. When you want to know how many items one table have the only option it has is to read all of them counting one by one. That is the exact task that the command mentioned in the beginning of this answer does. It scans the entire table counting all the items one by one.

Because of that, when you perform this task it will bill you the entire table read (DynamoDB bills you per reads and writes). And maybe after you started the scan someone put another item in the the table while you are still counting. In that case it will not restart the count because by design DynamoDB is eventually consistent.

Upvotes: 2

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