Apache Solr Reference Guide Covering Apache Solr 6.0

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Special Commands for the Data Import Handler
You can pass special commands to the DIH by adding any of the variables listed below to any row returned by
any component:
$skipDoc
$skipRow
Variable
Description
Skip the current document; that is, do not add it to Solr. The value can be the string tru
e|false.
Skip the current row. The document will be added with rows from other entities. The
value can be the string true|false
$docBoost Boost the current document. The boost value can be a number or the toString conve
rsion of a number.
$deleteDocById Delete a document from Solr with this ID. The value has to be the uniqueKey value of
the document.
$deleteDocByQuery
Delete documents from Solr using this query. The value must be a Solr Query.
Updating Parts of Documents
Once you have indexed the content you need in your Solr index, you will want to start thinking about your
strategy for dealing with changes to those documents. Solr supports two approaches to updating documents that
have only partially changed.
The first is atomic updates. This approach allows changing only one or more fields of a document without having
to re-index the entire document.
The second approach is known as optimistic concurrency or optimistic locking. It is a feature of many NoSQL
databases, and allows conditional updating a document based on its version. This approach includes semantics
and rules for how to deal with version matches or mis-matches.
Atomic Updates and Optimistic Concurrency may be used as independent strategies for managing changes to
documents, or they may be combined: you can use optimistic concurrency to conditionally apply an atomic
update.
Atomic Updates
Solr supports several modifiers that atomically update values of a document. This allows updating only specific
fields, which can help speed indexing processes in an environment where speed of index additions is critical to
the application.
To use atomic updates, add a modifier to the field that needs to be updated. The content can be updated, added
to, or incrementally increased if a number.
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