Re: [jira] Commented: (DERBY-649) Useful indexes not used in UNION ALL

[Satheesh Bandaram]

Thanks for reviewing the patch. Daniel John Debrunner wrote: Satheesh Bandaram (JIRA) wrote: I will also enhance this patch to make it more generic for trunk later. When you say <ColumnReference> <RELOP> <constant>, can the constant be a parameter? Yes, it can. And closely related, in the code (UnionNode.java) you say 'For now, we only push simple + * single column predicates that are binaryOperations.' Does this need to be clarified? Maybe state explictly what can be pushed down, maybe 'simple' to you, would be 'complex' to me? OK. I will expand the comments on this. Could you explain new the code in pushExpressionsIntoSelect? Since you have spent time on this, it would be great to capture your thoughts in the code comments. For example, why do we need a new nodes that represent '= TRUE', I'm sure it's required but to a reader of the code it's not obvious why. OK. I will add more comments. Great patch to improve performance! Dan.