Solr Schema Design Considerations

Indexed Fields

The number of indexed fields greatly increases the following:

  • Memory usage during indexing
  • Segment merge time
  • Optimization times
  • Index size

These effects can be reduced by the use of¬†omitNorms=”true”


    • This is arguably an advanced option.
    • Set to true to omit the norms associated with this field (this disables length normalization and index-time boosting for the field, and saves some memory). Only full-text fields or fields that need an index-time boost need norms.
  1. Choose between “text” and “string” field property

Stored fields

Retrieving the stored fields of a query result can be a significant expense. This cost is affected largely by the number of bytes stored per document–the higher byte count, the sparser the documents will be distributed on disk and more I/O is necessary to retrieve the fields (usually this is a concern when storing large fields, like the entire contents of a document).

Consider storing large fields outside of Solr. If you feel inclined to do so regardless, consider using compressed fields, which increase the CPU cost of storing and retrieving the fields, but lowers the I/O burden and CPU usage.

If you aren’t always using all the stored fields, then enabling lazy field loading can be a huge boon, especially if compressed fields are used.