facet.method=enum works by executing a query (against indexed values) for each indexed value in a given field (which, for indexed=false, is "no values"). So that explains why facet.method=enum no longer works. I was going to suggest that you might not want to set indexed=false on the docValues facet fields anyway, since the indexed values are still used for facet refinement (assuming your index is distributed).
What's the number of unique values in the relevant fields? If it's low enough, setting docValues=false and indexed=true and using facet.method=enum (with a sufficiently large filterCache) is definitely a viable option, and will almost certainly be faster than docValues-based faceting. (As an aside, noting for future reference: high-cardinality facets over high-cardinality DocSet domains might be able to benefit from a term facet count cache: https://issues.apache.org/jira/browse/SOLR-13807) I think you didn't specifically mention whether you acted on Erick's suggestion of setting "uninvertible=false" (I think Erick accidentally said "uninvertible=true") to fail fast. I'd also recommend doing that, perhaps even above all else -- it shouldn't actually *do* anything, but will help ensure that things are behaving as you expect them to! Michael On Wed, Jun 17, 2020 at 4:31 AM James Bodkin <james.bod...@loveholidays.com> wrote: > > Thanks, I've implemented some queries that improve the first-hit execution > for faceting. > > Since turning off indexed on those fields, we've noticed that > facet.method=enum no longer returns the facets when used. > Using facet.method=fc/fcs is significantly slower compared to > facet.method=enum for us. Why do these two differences exist? > > On 16/06/2020, 17:52, "Erick Erickson" <erickerick...@gmail.com> wrote: > > Ok, I see the disconnect... Necessary parts if the index are read from > disk > lazily. So your newSearcher or firstSearcher query needs to do whatever > operation causes the relevant parts of the index to be read. In this case, > probably just facet on all the fields you care about. I'd add sorting too > if you sort on different fields. > > The *:* query without facets or sorting does virtually nothing due to some > special handling... > > On Tue, Jun 16, 2020, 10:48 James Bodkin <james.bod...@loveholidays.com> > wrote: > > > I've been trying to build a query that I can use in newSearcher based > off > > the information in your previous e-mail. I thought you meant to build a > *:* > > query as per Query 1 in my previous e-mail but I'm still seeing the > > first-hit execution. > > Now I'm wondering if you meant to create a *:* query with each of the > > fields as part of the fl query parameters or a *:* query with each of > the > > fields and values as part of the fq query parameters. > > > > At the moment I've been running these manually as I expected that I > would > > see the first-execution penalty disappear by the time I got to query 4, > as > > I thought this would replicate the actions of the newSeacher. > > Unfortunately we can't use the autowarm count that is available as part > of > > the filterCache/filterCache due to the custom deployment mechanism we > use > > to update our index. > > > > Kind Regards, > > > > James Bodkin > > > > On 16/06/2020, 15:30, "Erick Erickson" <erickerick...@gmail.com> wrote: > > > > Did you try the autowarming like I mentioned in my previous e-mail? > > > > > On Jun 16, 2020, at 10:18 AM, James Bodkin < > > james.bod...@loveholidays.com> wrote: > > > > > > We've changed the schema to enable docValues for these fields and > > this led to an improvement in the response time. We found a further > > improvement by also switching off indexed as these fields are used for > > faceting and filtering only. > > > Since those changes, we've found that the first-execution for > > queries is really noticeable. I thought this would be the filterCache > based > > on what I saw in NewRelic however it is probably trying to read the > > docValues from disk. How can we use the autowarming to improve this? > > > > > > For example, I've run the following queries in sequence and each > > query has a first-execution penalty. > > > > > > Query 1: > > > > > > q=*:* > > > facet=true > > > facet.field=D_DepartureAirport > > > facet.field=D_Destination > > > facet.limit=-1 > > > rows=0 > > > > > > Query 2: > > > > > > q=*:* > > > fq=D_DepartureAirport:(2660) > > > facet=true > > > facet.field=D_Destination > > > facet.limit=-1 > > > rows=0 > > > > > > Query 3: > > > > > > q=*:* > > > fq=D_DepartureAirport:(2661) > > > facet=true > > > facet.field=D_Destination > > > facet.limit=-1 > > > rows=0 > > > > > > Query 4: > > > > > > q=*:* > > > fq=D_DepartureAirport:(2660+OR+2661) > > > facet=true > > > facet.field=D_Destination > > > facet.limit=-1 > > > rows=0 > > > > > > We've kept the field type as a string, as the value is mapped by > > application that accesses Solr. In the examples above, the values are > > mapped to airports and destinations. > > > Is it possible to prewarm the above queries without having to > define > > all the potential filters manually in the auto warming? > > > > > > At the moment, we update and optimise our index in a different > > environment and then copy the index to our production instances by > using a > > rolling deployment in Kubernetes. > > > > > > Kind Regards, > > > > > > James Bodkin > > > > > > On 12/06/2020, 18:58, "Erick Erickson" <erickerick...@gmail.com> > > wrote: > > > > > > I question whether fiterCache has anything to do with it, I > > suspect what’s really happening is that first time you’re reading the > > relevant bits from disk into memory. And to double check you should have > > docVaues enabled for all these fields. The “uninverting” process can be > > very expensive, and docValues bypasses that. > > > > > > As of Solr 7.6, you can define “uninvertible=true” to your > > field(Type) to “fail fast” if Solr needs to uninvert the field. > > > > > > But that’s an aside. In either case, my claim is that > first-time > > execution does “something”, either reads the serialized docValues from > disk > > or uninverts the file on Solr’s heap. > > > > > > You can have this autowarmed by any combination of > > > 1> specifying an autowarm count on your queryResultCache. > That’s > > hit or miss, as it replays the most recent N queries which may or may > not > > contain the sorts. That said, specifying 10-20 for autowarm count is > > usually a good idea, assuming you’re not committing more than, say, > every > > 30 seconds. I’d add the same to filterCache too. > > > > > > 2> specifying a newSearcher or firstSearcher query in > > solrconfig.xml. The difference is that newSearcher is fired every time a > > commit happens, while firstSearcher is only fired when Solr starts, the > > theory being that there’s no cache autowarming available when Solr fist > > powers up. Usually, people don’t bother with firstSearcher or just make > it > > the same as newSearcher. Note that a query doesn’t have to be “real” at > > all. You can just add all the facet fields to a *:* query in a single > go. > > > > > > BTW, Trie fields will stay around for a long time even though > > deprecated. Or at least until we find something to replace them with > that > > doesn’t have this penalty, so I’d feel pretty safe using those and > they’ll > > be more efficient than strings. > > > > > > Best, > > > Erick > > > > > > >
