DynamoDB loading old local database file

Question

A while ago I loaded a bunch of JSON data into a local DynamoDB instance for practice. I did some queries and stored the data into a CSV and ended up closing my connection.

So I have this sample_data.db file on my laptop that's 7GB and need to access it again. Normally when I create a DynamoDB instance, I say:

java \
    -Djava.library.path=./DynamoDBLocal_lib \
    -jar DynamoDBLocal.jar \
    -dbPath /Users/myname/Documents/data/sample_data.db

So I did that to create the file but how do I now open another connection to that pre-existing file? Whenever I do the above, it just says:

Invalid directory for database creation.

Clearly that means the above command is only for creating a new DB - sorry if this is a trivial question but how do I open a connection to an old one?

Do I have to upload it to AWS somehow? Or is there a way?

EDIT: I was using this as a reference, but didn't see a command to specify path to a pre-existing DB. http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/DynamoDBLocal.html

Answer 1

The problem is rooted in the fact that local DynamoDB does not allow you to directly specify the database file name, only the path where the file should be stored/loaded. The file name(s) is/are derived from your AWS access key for DynamoDB local and the AWS region. Alternately, if you specify the -sharedDb option, the single database file is stored as shared-local-instance.db. The -dbPath option defines where the DynamoDB local instance should look for these database files.

In order to load your old database file, I would recommend renaming it to conform to the naming conventions (so that DynamoDB will recognize it), and specifying the -dbPath option without the filename part. Hopefully, this will allow you to access your data.

Example:

mv sample_data.db shared-local-instance.db
java \
    -Djava.library.path=./DynamodDBLocal_lib \
    -jar DynamoDBLocal.jar \
    -dbPath /Users/myname/Documents/data

Note: the database file naming is a little vaguely defined (at least, my very limited search for naming criteria didn't turn up much). You may need to play around with it a bit to figure out the exact naming that is expected.