> On Mar 20, 2017, at 12:14 AM, Hussain Pirosha <hussain.piro...@impetus.co.in> > wrote: > > Thanks Julian. > > Spending more time with calcite code on computing cost, I have few questions. > > 1. The cost of the plan is the sum of all the converted (datasource > specific) RelNodes ?
Yes. The cost of a plan is the sum of the costs of its constituent RelNodes. > 2. the computeSelfCost method shall calculate the cost by using the > RelMetaDataQuery. Can you point to some example or impl where RelMetaData has > been implemented or can be used as a reference? Not sure what you mean. There is no “RelMetaData” class or interface. RelMetadataTest should give you some clues (especially if you run it in a debugger). I’m not the best person to write the documentation you need. Has anyone implemented a metadata provider in a project that uses Calcite? If so, please share what worked. Julian
