<br><font size=2 face="sans-serif">Hello,</font>
<br>
<br><font size=2 face="sans-serif">For implementing Sql with Grouping Set
we need to change the way the following classes interact during loading
of Cell request data.</font>
<br>
<br><font size=2 face="sans-serif">1. fastBatchingCellReader.loadAggregations()
-> batch.loadAggregation()</font>
<br><font size=2 face="sans-serif">2. batch.loadAggregation() -> aggregationManager.loadAggregation()</font>
<br><font size=2 face="sans-serif">3. aggregationManager.loadAggregation()
-> aggregation.load()</font>
<br><font size=2 face="sans-serif">4. aggregation.load() -> Segment.load()</font>
<br>
<br><font size=2 face="sans-serif">Using SQL with Grouping Set function
needs to be decided at the Batch level, once we identify the batches that
can be grouped then we need to tag them together and pass this information
down to Segment.load() to fire single SQL for multiple batches.</font>
<br>
<br><font size=2 face="sans-serif">Segment.load() static method needs information
about all the segment instances which are going to be queried together
along with some additional information from Aggregation/Batch class.</font>
<br>
<br><font size=2 face="sans-serif">So we need to put together all the segment
instances from multiple grouped batches and pass it to Segment.load().</font>
<br>
<br><font size=2 face="sans-serif">We are thinking of the following approach
to achieve this,</font>
<br>
<br><font size=2 face="sans-serif">Instead of aggregation.load() calling
Segment.load() with its Segments list, aggregation.load() need to return
Segment list of each batch to the FBCR(or class representing Grouped Batch).</font>
<br><font size=2 face="sans-serif">Then FBCR will group the segments of
grouped batches and make a call to Segment.load static method to fire single
sql with grouping sets and populate all those Segments.</font>
<br>
<br><font size=2 face="sans-serif">We are close to finishing a working
prototype based on the above approach.</font>
<br><font size=2 face="sans-serif">Hence would like to get your early feedback
to ensure that we are on right track.</font>
<br>
<br><font size=2 face="sans-serif">Code posted at http://forums.pentaho.org/showthread.php?t=53644
is POC for logic of grouping the Batch and extracting information from
a grouping set sql to multiple segments of multiple batches.</font>
<br>
<br><font size=2 face="sans-serif">Thanks,</font>
<br><font size=2 face="sans-serif">Thiyagu</font>
<br>
<br><font size=2 face="sans-serif"> </font>
<br>