Do not use Solr as a database. It was never designed to be a database. It is missing a lot of features that are normal in databases.
* no transactions * no rollback (in Solr Cloud) * no session isolation (one client’s commit will commit all data in progress) * no schema migration * no version migration * no real backups (Solr backup is a cold server, not a dump/load) * no dump/load * modify record (atomic updates are a subset of this) Solr assumes you can always reload all the data from a repository. This is done instead of migration or backups. If you use Solr as a database and lose all your data, don’t blame us. It was never designed to do that. wunder Walter Underwood wun...@wunderwood.org http://observer.wunderwood.org/ (my blog) > On Sep 17, 2018, at 7:01 AM, Jan Høydahl <jan....@cominvent.com> wrote: > >> We are beginners to Apache SOLR, We need following clarifications from you. >> >> >> >> 1. In SOLRCloud, How can we install more than one Shared on Single PC? > > You typically have one installation of Solr on each server. Then you can add > a collection with multiple shards, specifying how many shards you wish when > creating the collection, e.g. > > bin/solr create -c mycoll -shards 4 > > Although possible, it is normally not advised to install multiple instances > of Solr on the same server. > >> 2. How many maximum number of shared can be added under on SOLRCloud? > > There is no limit. You should find a good number based on the number of > documents, the size of your data, the number of servers in your cluster, > available RAM and disk size and the required performance. > > In practice you will guess the initial #shards and then benchmark a few > different settings before you decide. > Note that you can also adjust the number of shards as you go through > CREATESHARD / SPLITSHARD APIs, so even if you start out with few shards you > can grow later. > >> 3. In my application there is no need of ACID properties, other than >> this can I use SOLR as a Complete Database? > > You COULD, but Solr is not intended to be your primary data store. You should > always design your system so that you can re-index all content from some > source (does not need to be a database) when needed. There are several use > cases for a complete re-index that you should consider. > >> 4. In Which OS we can feel the better performance, Windows Server OS / >> Linux? > > I'd say Linux if you can. If you HAVE to, then you could also run on Windows > :-) > >> 5. If a SOLR Core contains 2 Billion indexes, what is the recommended >> RAM size and Java heap space for better performance? > > It depends. It is not likely that you will ever put 2bn docs in one single > core. Normally you would have sharded long before that number. > The amount of physical RAM and the amount of Java heap to allocate to Solr > must be calculated and decided on a per case basis. > You could also benchmark this - test if a larger RAM size improves > performance due to caching. Depending on your bottlennecks, adding more RAM > may be a way to scale further before needing to add more servers. > > Sounds like you should consult with a Solr expert to dive deep into your > exact usecase and architect the optimal setup for your case, if you have > these amounts of data. > >> 6. I have 20 fields per document, how many maximum number of documents >> can be inserted / retrieved in a single request? > > No limit. But there are practical limits. > For indexing (update), attempt various batch sizes and find which gives the > best performance for you. It is just as important to do inserts (updates) in > many parallell connections as in large batches. > > For searching, why would you want to know a maximum? Normally the usecase for > search is to get TOP N docs, not a maximum number? > If you need to retrieve thousands of results, you should have a look at > /export handler and/or streaming expressions. > >> 7. If I have Billions of indexes, If the "start" parameter is 10th >> Million index and "end" parameter is start+100th index, for this case any >> performance issue will be raised ? > > Don't do it! > This is a warning sign that you are using Solr in a wrong way. > > If you need to scroll through all docs in the index, have a look at streaming > expressions or cursorMark instead! > >> 8. Which .net client is best for SOLR? > > The only I'm aware of is SolrNET. There may be others. None of them are > supported by the Solr project. > >> 9. Is there any limitation for single field, I mean about the size for >> blob data? > > I think there is some default cutoff for very large values. > > Why would you want to put very large blobs into documents? > This is a warning flag that you may be using the search index in a wrong way. > Consider storing large blobs outside of the search index and reference them > from the docs. > > > In general, it would help a lot if you start telling us WHAT you intend to > use Solr for, what you try to achieve, what performance goals/requirements > you have etc, instead of a lot of very specific max/min questions. There are > very seldom hard limits, and if there are, it is usually not a good idea to > approach them :) > > Jan >
