Apache Solr Reference Guide Covering Apache Solr 6.0

StreamFactory streamFactory = new
StreamFactory().withCollectionZkHost("collection1", zkServer.getZkAddress())
.withStreamFunction("search", CloudSolrStream.class)
.withStreamFunction("unique", UniqueStream.class)
.withStreamFunction("top", RankStream.class)
.withStreamFunction("group", ReducerStream.class)
.withStreamFunction("parallel", ParallelStream.class);
ParallelStream pstream =
(ParallelStream)streamFactory.constructStream("parallel(collection1,
group(search(collection1, q=\"*:*\", fl=\"id,a_s,a_i,a_f\", sort=\"a_s asc,a_f
asc\", partitionKeys=\"a_s\"), by=\"a_s asc\"), workers=\"2\",
zkHost=\""+zkHost+"\", sort=\"a_s asc\")");
Data Requirements
Because streaming expressions relies on the /export handler, many of the field and field type requirements to
use /export are also requirements for /stream, particularly for sort and fl parameters. Please see the
section Exporting Result Sets for details.
Stream Sources
Stream sources originate streams. There are currently five stream sources available: search, jdbc, facet, stats,
and topic.
search
The search function searches a SolrCloud collection and emits a stream of tuples that match the query. This is
very similar to a standard Solr query, and uses many of the same parameters.
This expression allows you to specify a request hander using the qt parameter. By default the /select handler
is used. The /select handler can be used for simple rapid prototyping of expressions. For production, however,
you will most likely want to use the /export handler which is designed to sort and export entire result sets.
The /export handler is not used by default because it has much stricter requirements then the /select handl
er so it's not as easy to get started working with. To read more about the /export handler requirements review
the section Exporting Result Sets.
Parameters
Syntax
collection: (Mandatory) the collection being searched.
q: (Mandatory) The query to perform on the Solr index.
fl: (Mandatory) The list of fields to return.
sort: (Mandatory) The sort criteria.
zkHost: Only needs to be defined if the collection being searched is found in a different zkHost than the
local stream handler.
qt: Specifies the query type, or request handler, to use. Set this to /export to work with large result
sets. The default is /select.
rows: (Mandatory with the /select handler) The rows parameter specifies how many rows to return.
This parameter is only needed with the /select handler (which is the default) since the /export handle
r always returns all rows.
Apache Solr Reference Guide 6.0
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