Load Snapshot Data with <snapshot> or <raql>
You can load snapshots of mashable or mashup results as dataset streams for analysis in RAQL queries using the:
<snapshot>EMML extension statement. This statement both creates a streaming variable to hold the snapshot dataset and executes the SQL query to retrieve snapshots from the
Presto Snapshot Repository. See
Load Snapshots in a Named Variable for an example.
<raql>EMML extension statement with the
snapshotquery attribute to load the dataset. This uses a local variable, named
snapshots to hold the dataset stream which is only in scope for this
RAQL query. See
Load Snapshots Anonymously for an example.
Before you can query snapshots, you must register the mashable or create the mashup with results you want to use. You must also run the mashable or mashup and take at least one snapshot.
