Many applications in the enterprise world store their important data in relational databases. The databases become one of the important data sources for Apache Solr for searching. Apache Solr provides
DataImportHandler to deal with this type of data source. With
DataImportHandler, you can also load only the deltas instead of the complete data set again and again. Many times, this can be set as off-time scheduled job activity to minimize the impact of indexing on day-to-day work. In case of real-time updates, this activity has to be scheduled with a fixed frequency.
DataImportHandler supports pull mechanism, but in the newer release of Apache Solr,
DataImportHandler supports push operation ...