Dynamodb GSI 包含 boolean

Question

I have a dynamodb table of events that have specified start and end times. These events can be happening in realtime, in which case, the end timestamp is not yet written.

I have setup a global secondary index with the sort key being the binary field, active . When I try and update a record to set this to true, I get the error:

Expected: B Actual: BOOL

The python code for this is:

table.update_item(
    Key={
        'fingerprint': item['fingerprint'],
        'startedtimestamp': item['startedtimestamp']
    },
    UpdateExpression="SET #active :active, resolvedtimestamp :resolvedtimestamp",
    ExpressionAttributeNames : {
        '#active' : 'active',
        '#resolvedtimestamp' : 'resolvedtimestamp'
    },
    ExpressionAttributeValues={
        ':active': False, ':resolvedtimestamp': resolvedtimestamp},
)

I have also been reading elsewhere about using a sparse index instead. In this case though, if the index was just the resolvedtimestamp , would it be possible to query for the active records (eg resolvedtimestamp is not set)? Otherwise, what other optimizations can I do to the table and indices to be able to query for active records?

Answer 1

I have setup a global secondary index with the sort key being the binary field, active

active is a boolean not a binary field and that is why you receive the exception. Also, it's not possible to use boolean as part of a primary key, it must be string, number or binary.

If you are only interested in active records, then set active = 'True' only when true, do not set it to false. If false, delete the attribute from the item. This will give you a sparse index.

table.update_item(
    Key={
        'fingerprint': item['fingerprint'],
        'startedtimestamp': item['startedtimestamp']
    },
    UpdateExpression="SET #active = :active, resolvedtimestamp = :resolvedtimestamp",
    ExpressionAttributeNames : {
        '#active' : 'active',
        '#resolvedtimestamp' : 'resolvedtimestamp'
    },
    ExpressionAttributeValues={
        ':active': 'True', 
        ':resolvedtimestamp': resolvedtimestamp},
)

Answer 2

Please update your Update Expression with.

 UpdateExpression="SET #active = :active, resolvedtimestamp = :resolvedtimestamp",