Delete all items (clear) in a DynamoDB table using bash

clearTable.sh

#!/bin/bash

TABLE_NAME=TableName
KEY=id

aws dynamodb scan --table-name $TABLE_NAME --attributes-to-get "$KEY" --query "Items[].id.S" --output text | tr "\t" "\n" | xargs -t -I keyvalue aws dynamodb delete-item --table-name $TABLE_NAME --key '{"id": {"S": "keyvalue"}}'

I noticed that the "KEY=id" is not used and it looks like "id" in aws cli commande is hardcoded 😃

yeah, here's an alternate version:

aws dynamodb scan --table-name $TABLE_NAME --attributes-to-get "$KEY" \
  --query "Items[].$KEY.S" --output text | \
  tr "\t" "\n" | \
  xargs -t -I keyvalue aws dynamodb delete-item --table-name $TABLE_NAME \
  --key "{\"$KEY\": {\"S\": \"keyvalue\"}}"

what if the result has more than 1MB is size ?

I think it won't work when the table has both the hask key and the sort key.

You also need --region in both aws subcommands (in my build, anyway).

I wonder if there's a faster way of doing this. While it's often not necessary to optimize code, this particular one could do with something quicker. I guess you could drop and recreate your table (using the json out of aws describe-table).

@chetanmelkani is correct - this won't work if there is also a sort key

@lqueryvg - Good point.

Here's a modified version of the above command line which will scan a dynamo table and delete each item in the table. It works for tables which have both a partition and a sort key.

This command uses an AWS CLI profile named "admin" so change it to whichever profile name works for you
This command assumes the partition and sort keys are both of Dynamo type "S" (string) and so alter the attribute types as needed
Change the values of these three enviornment variables to match your table name as well as the names of its partition and sort keys/columns/attributes

export DYNAMO_TABLE="MyTableName"
export DYN_HASH_KEY="MyPartitionKeyName"
export DYN_SORT_KEY="MySortKeyName"

In one command, delete all items in a dynamo table which has both partition and sort keys

aws --profile admin dynamodb scan --table-name ${DYNAMO_TABLE} --attributes-to-get "${DYN_HASH_KEY}" "${DYN_SORT_KEY}" --output text | awk -v DYNAMO_TABLE="$DYNAMO_TABLE" -v DYN_HASH_KEY="$DYN_HASH_KEY" -v DYN_SORT_KEY="$DYN_SORT_KEY" '/PK_HASH/{ HASH=$2; next } /PK_SORT/{ print "aws --profile admin dynamodb delete-item --table-name " DYNAMO_TABLE " --key "{\"" DYN_HASH_KEY "\": {\"S\": \"" HASH "\"},\"" DYN_SORT_KEY "\": {\"S\": \"" $2 "\"}}"\0" }' | xargs -t -0 bash -c

UPDATE: I just noticed that there's still a hard-coded attribute/column name that's not using DYN_HASH_KEY and DYN_SORT_KEY. My table's partition/hash and sort keys are named "PK_HASH" and "PK_SORT" - and you can see they're hard-coded in the above command. So it won't actually work for you unless you modify PK_HASH and PK_SORT to match your own table's hash and sort key names. I'll see if I can fix this, but I'm having difficulty with awk's conditional expressions accepting the awk environment variables in the comparison expression.

Is there a way I can delete all items with different sort keys but the same PK?

That should be doable. Starting from @OtterFlip's work you'll want to replace the "dynamodb scan" with "dynamodb query" and add a "--key-condition-expression" to specify the value of your PK. Check out the docs for details on that.