Migrate Mashups using RAQL for Presto 3.6.1
Changes in the semantics in how datasets are stored in and retrieved from Presto Analytics In-Memory Stores between version 3.6 and 3.6.1 require updates to mashups that use the <storeto> or <loadfrom> extension statements.
To keep the existing semantics, add a version="1.0" attribute to each <storeto> or <loadfrom> statement in your existing mashups. For example:
<storeto version="1.0" key="stocks2011" variable="stocksDS"/>
...
<loadfrom version="1.0" key="stocks2011"
variable="stocks"/>
To migrate to the new 3.6.1 semantics for existing mashups, you must: Use a unique
In-Memory Store name in the
cache attribute to identify where each dataset should be stored or retrieved from.
Specify the method to assign unique keys when a dataset is stored.
In the previous release overwriting existing data was the default requiring explicit markup to have datasets appended to existing data. In this release, appending data is now the default, requiring explicit markup to clear existing data instead. To ensure mashups keep their existing semantics:
Add clearcache = "true" to any existing mashup that uses the <storeto> statement but does not use the append attribute.
Remove the append attribute from any <storeto> statements.
For example:
<storeto cache="myStocks2011" key="#unique"
variable="stocksDS" clearcache="true"/>
...
<loadfrom cache="myStocks2011" variable="stocks"/>
