Thanks Dawid, glad I asked! Am Dienstag, den 25.09.2018, 10:46 +0200 schrieb Dawid Weiss: > Use MMapDirectory on a temporary location, Matthias. If you really > need in-memory indexes, a new Directory implementation is coming > (RAMDirectory will be deprecated, then removed), but the difference > compared to MMapDirectory is typically not worth the hassle. See this > issue for more discussion. > > https://issues.apache.org/jira/browse/LUCENE-8438 > > Dawid > On Tue, Sep 25, 2018 at 10:44 AM Matthias Müller > <matthias_muel...@tu-dresden.de> wrote: > > > > Hi, > > > > Lucene provides different storage options for in-memory indexes. I > > found three structures that would qualify for the task: > > > > * RamDirectory (which I currently use for prototyping, but wonder > > if it > > is the ideal choice for my task) > > * MemoryIndex, which claims to have better performance and resource > > use > > for small documents > > * MMapDirectory which should outperform RamDirectory for huge > > indices > > (what is "huge?") > > > > > > My plan is to periodically index some properties (string codes, > > longs, > > lat/lng points) of a larger database content with Lucene for > > quicker > > lookups (compared to slow SQL queries). > > > > What would be the most efficient (or intended) storage option for > > such > > an index in terms of lookup speed and CPU/memory use? Below [1] is > > a > > brief summary of the index contents and I hope these figures are > > sufficient to get a recommendation. But I am also happy to study > > more > > detailed documentation on the matter. > > > > - Matthias > > > > [1]: Summary of index contents and intended use > > * Total documents: 500.000 - 1.000.000, may grow to 10.000.000 > > records > > in mid future. > > * Document fields (all of them single value fields): > > * String (9x), usually 1-10 characters long, mostly recurring > > values (5% distinct) > > * LongPoint (4x), two fields contain mostly distinct values, > > one > > lostly recurring values (5-10% distinct), one field acts as a > > primary > > key > > * LatLonPoint (1x), 30% distinct > > * Refresh interval: 1..5 minutes (I currently create a fresh index > > instance on each update and discard the old one) > > * Most queries are range queries and exact matches on several > > properties, sometimes I need to retrieve the property fields of a > > single document based on a primary key value. > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > For additional commands, e-mail: java-user-h...@lucene.apache.org >
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