(PECL solr >= 0.9.2)
SolrInputDocument::merge — Merges one input document into another
Merges one input document into another.
sourceDoc
The source document.
overwrite
If this is TRUE
it will replace matching fields in the destination document.
Returns TRUE
on success or FALSE
on failure. In the future, this will be modified to return the number of fields in the new document.