Hi Carolina, This issue came up recently in one of the Drill Slack channels. I wonder, can anyone here summarize the findings from that Slack discussion?
Thanks, - Paul On Mon, Sep 21, 2020 at 7:35 AM Carolina Gomes <[email protected]> wrote: > Also if it helps, I’m using Drill 1.16 in single-node mode. > > On Mon, Sep 21, 2020 at 10:32 AM Carolina Gomes <[email protected]> > wrote: > > > Hi all, > > > > I have a question about push down of limit and offset clauses on Drill. > > For my use case, I’d always like for limit and offset clauses to be > pushed > > down to the data sources, which are always RDBMS databases like SQL > Server, > > Oracle etc. > > > > > > However, I have noticed the decision to push down seems to happen > > depending on the size of the limit clause, and on the number of columns > > being projected. > > > > > > As an example, I have a table of about 250 columns with about 50 million > > rows. If I do: > > > > > > select * from table limit 1000 —-> limit push down does not happen, query > > takes 30s while if I change the physical plan to push down the limit > > clause, it takes less than 1s. > > > > select * from table limit 1000000 —-> limit push down does happen, query > > takes roughly same time as if I queried directly on the source DB. > > > > Is there a way of easily telling Drill to always pushdown? > > -- > > [Carolina Gomes] > > CEO, AfterData.ai <https://www.afterdata.ai/> > > +1 (416) 931 4774 > > > > > > > > -- > [Carolina Gomes] > CEO, AfterData.ai <https://www.afterdata.ai/> > +1 (416) 931 4774 >
