Cool! I would be happy to be looped in occasionally as well - so I will
watch this space for the public progress updates. In addition to adding
the algorithm, we'll need to add an optimizer rule (actually update an
existing rule) so that it gets picked when appropriate - and also a hint
so that you can manually suggest that it be picked regardless. DB2
chooses this join method when the incoming data arguments are already
sorted, so that would likely be a good heuristic for us too. (It is
sure to be cheaper than anything else in that case.) (So think about
this as adding a Merge Join, not a Sort Merge Join, actually, as is not
likely to be the case that sorting and then doing this will be a cost win.)
On 5/26/19 9:22 PM, Stephen Ermshar (gmail) wrote:
Hi Ali,
Since the coding period starts tomorrow I wanted to get in touch with you again.
Preston and I were thinking it would be good to post weekly reports here on the
dev mailing list to keep a public record of our progress. We’d also like to
have weekly or twice-weekly meetings to track our progress and direction. If
you have any thoughts on how we can organize our efforts more this summer let
me know.
This week Preston and I decided we’d focus on refreshing my knowledge of the
Sort Merge Join algorithm. I’d like to also get a fresh development environment
setup for this summer and if possible start moving old code in from the
outdated repository.
I’m excited to start working on this!
- Stephen Ermshar
