Apache Solr Reference Guide Covering Apache Solr 6.0

Retrieving DocValues During Search
Field values retrieved during search queries are typically returned from stored values. However, non-stored
docValues fields will be also returned along with other stored fields when all fields (or pattern matching globs) are
specified to be returned (e.g. " fl=* ") for search queries depending on the effective value of the useDocValues
AsStored parameter for each field. For schema versions >= 1.6, the implicit default is useDocValuesAsStor
ed="true" . See Field Type Definitions and Properties & Defining Fields for more details.
When useDocValuesAsStored="false" , non-stored DocValues fields can still be explicitly requested by
name in the fl param , but will not match glob patterns ("*").
Note that returning DocValues along with "regular" stored fields at query time has performance implications that
stored fields may not because DocValues are column-oriented and may therefore incur additional cost to retrieve
for each returned document. Also note that while returning non-stored fields from DocValues, the values of a
multi-valued field are returned in sorted order (and not insertion order). If you require the multi-valued fields to be
returned in the original insertion order, then make your multi-valued field as stored (such a change requires
re-indexing).
In cases where the query is returning only docValues fields performance may improve since returning stored
fields requires disk reads and decompression whereas returning docValues fields in the fl list only requires
memory access.
When retrieving fields from their docValues form, two important differences between regular stored fields and
docValues fields must be understood:
1. Order is not preserved. For simply retrieving stored fields, the insertion order is the return order. For
docValues, it is the sorted order.
2. Multiple identical entries are collapsed into a single value. Thus if I insert values 4, 5, 2, 4, 1, my return will
be 1, 2, 4, 5.
Schemaless Mode
Schemaless Mode is a set of Solr features that, when used together, allow users to rapidly construct an effective
schema by simply indexing sample data, without having to manually edit the schema. These Solr features, all
controlled via solrconfig.xml, are:
1. Managed schema: Schema modifications are made at runtime through Solr APIs, which requires the use
of schemaFactory that supports these changes - see Schema Factory Definition in SolrConfig for more
details.
2. Field value class guessing: Previously unseen fields are run through a cascading set of value-based
parsers, which guess the Java class of field values - parsers for Boolean, Integer, Long, Float, Double,
and Date are currently available.
3. Automatic schema field addition, based on field value class(es): Previously unseen fields are added to the
schema, based on field value Java classes, which are mapped to schema field types - see Solr Field
Types.
Using the Schemaless Example
The three features of schemaless mode are pre-configured in the data_driven_schema_configs config set i
n the Solr distribution. To start an example instance of Solr using these configs, run the following command:
bin/solr start -e schemaless
This will launch a Solr server, and automatically create a collection (named " gettingstarted")
that contains
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