FWIW, you can pass ranges of arbitrary number of shards to SPLITSHARD. Thus you can split on any number of shards.
On Wed, Apr 5, 2017 at 5:39 PM, Erick Erickson <erickerick...@gmail.com> wrote: > You may be confusing the number of shards you configure and how they > expand using the SPLITSHARD command. That command creates two shards > where there was one before, so in that sense Solr collections can grow > by a factor of 2. But that doesn't mean anything about the number of > shards you started with. I.e. I can start with 3 shards, then use > SPLITSHARD and have 6, use SPLITSHARD again and have 12 etc.... > > Best, > Erick > > On Tue, Apr 4, 2017 at 9:22 PM, Walter Underwood <wun...@wunderwood.org> > wrote: > >> On Apr 4, 2017, at 7:38 PM, Muhammad Imad Qureshi > <imadgr...@yahoo.com.INVALID> wrote: > >> > >> Hi > >> I was recently told that ideally the number of shards in a SOLR cluster > should be equal to a power of 2. If this is indeed a best practice, then > what is the rationale behind this recommendation? ThanksImad > > > > I don’t know of any such recommendation. Assuming you are not RAM or > disk limited, going to two or three shards won’t help a lot. If those get > you out of a bottleneck, you’ll see a difference. > > > > I believe that some of the performance of Solr is proportional to the > number of distinct terms in the index (the vocabulary). A rule of thumb is > the vocabulary is proportional to the square root of the number of terms in > the index. Which is often related to the number of documents. With this > assumption, four shards gives a 2X speedup. Which has worked for me. > > > > wunder > > Walter Underwood > > wun...@wunderwood.org > > http://observer.wunderwood.org/ (my blog) > > > -- Sincerely yours Mikhail Khludnev
