Yes. Once per query is fine. Theoretically we could fire the rule many times inside a single query and I was saying we preferably cache in the context of a single query.
On Thu, Apr 30, 2015 at 5:57 PM, Adam Gilmore <dragoncu...@gmail.com> wrote: > We'll need to look it up at least once per query, though, right? Because > session variables can change query to query. Would you suggest I cached > the actual setting(s) as soon as the rule is instantiated? The rule is > only called once or twice per query, I think. > > On Fri, May 1, 2015 at 10:54 AM, Jacques Nadeau <jacq...@apache.org> > wrote: > > > Creating it at rule creation time is good. The key is we want to cache > it > > so we don't have to look it up every single time the rule fires. I think > > your point about specific versus general and PlannerSettings makes sense. > > > > On Thu, Apr 30, 2015 at 5:17 PM, Adam Gilmore <dragoncu...@gmail.com> > > wrote: > > > > > Moreover, I'm a tad wary about using PlannerSettings as they seem very > > > generic (i.e. not specific to a particular storage/format plugin, for > > > example). I've used "store.parquet.enable_pushdown_filter" as the > > option, > > > as it's very specific to the Parquet format plugin. I imagine I can > > still > > > use getOptions() to get that option from PlannerSettings, but it feels > a > > > bit more like we should be using QueryContext like PruneScanRule uses. > > > > > > What do you think? > > > > > > On Fri, May 1, 2015 at 10:13 AM, Adam Gilmore <dragoncu...@gmail.com> > > > wrote: > > > > > > > I actually patched the StorageEnginePlugin and FormatPlugin to pass > > > > QueryContext right through the chain of getting optimizer rules (as > is > > > the > > > > case for getting basic rules, etc.). This seemed to me like the most > > > > logical approach and aligned with something like your PruneScanRule. > > > > > > > > Do you think I should revert back and use the example you gave? > > > > > > > > P.S. The pushdown filter has improved performance significantly for > > > > certain types of queries. It mostly comes back to how well the data > is > > > > ordered and how often it can exclude row groups. Ideally, we should > be > > > > excluding individual pages as well, but from what I can see even the > > > reader > > > > from the Parquet library does not yet do this. > > > > > > > > On Thu, Apr 30, 2015 at 4:14 PM, Jacques Nadeau <jacq...@apache.org> > > > > wrote: > > > > > > > >> PlannerSettings is the primary we expose settings that need to be > > > >> interrogated during planning (e.g. in an optimizer rule). You can > get > > > >> ahold of this by doing: > > > >> > > > >> PlannerSettings settings = > > > PrelUtil.getPlannerSettings(call.getPlanner()); > > > >> > > > >> PlannerSettings then has access to session settings. > > > >> > > > >> You can see an example of this at [1] > > > >> > > > >> I'm excited to see the impact of this. Look forward to seeing the > > > patch! > > > >> > > > >> [1] > > > >> > > > >> > > > > > > https://github.com/apache/drill/blob/master/exec/java-exec/src/main/java/org/apache/drill/exec/planner/physical/NestedLoopJoinPrule.java#L82 > > > >> > > > >> > > > >> On Wed, Apr 29, 2015 at 11:06 PM, Adam Gilmore < > dragoncu...@gmail.com > > > > > > >> wrote: > > > >> > > > >> > Hi guys, > > > >> > > > > >> > I'm trying to work out how I could access the QueryContext inside > > > >> > a StoragePluginOptimizerRule. > > > >> > > > > >> > I've basically implemented the Parquet pushdown filtering, but I > > > really > > > >> > need to access the session settings (for whether or not we're > using > > > the > > > >> new > > > >> > Parquet reader so we can completely pushdown a filter and also for > > > >> > providing a setting to enable/disable pushdown filters). > > > >> > > > > >> > I've looked in a fair bit of detail, but there doesn't seem to be > a > > > way > > > >> to > > > >> > access this. > > > >> > > > > >> > If this is not the way I should be implementing it, can anyone > make > > > some > > > >> > suggestions? I really want to do full pushdown when using the new > > > >> Parquet > > > >> > reader, but I have no easy way to detect it's going to be used. > > > >> > > > > >> > P.S. In cases where we "fall back" to the new Parquet reader, I > > don't > > > >> do a > > > >> > full pushdown (as detecting that is done further down than the > > > planner). > > > >> > This could be fixed in the future, but for now I'm happy for just > > when > > > >> that > > > >> > setting is true. > > > >> > > > > >> > > > > > > > > > > > > > >
