[SOLR-13681] make Lucene's index sorting directly configurable in Solr

• Type: New Feature
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Assignee: Unassigned
• Reporter: Christine Poerschke
• Created: 07/Aug/19 15:42
• Updated: 27/May/22 18:52

Description

History/Background:

• SOLR-5730 made Lucene's SortingMergePolicy and EarlyTerminatingSortingCollector configurable in Solr 6.0 or later.
• LUCENE-6766 make index sorting a first-class citizen in Lucene 6.2 or later.

Current status:

• In Solr 8.2 use of index sorting is only available via configuration of a (top-level) merge policy that is a SortingMergePolicy and that policy's sort is then passed to the index writer config via the

  if (mergePolicy instanceof SortingMergePolicy) {
    Sort indexSort = ((SortingMergePolicy) mergePolicy).getSort();
    iwc.setIndexSort(indexSort);
  }
  

  https://github.com/apache/lucene-solr/blob/releases/lucene-solr/8.2.0/solr/core/src/java/org/apache/solr/update/SolrIndexConfig.java#L241-L244 code path.

Proposed change:

• in-scope for this ticket: To add direct support for index sorting configuration in Solr.
• out-of-scope for this ticket: deprecation and removal of SortingMergePolicy support

Issue Links

• duplicates: SOLR-12230 Deprecate SortingMergePolicy
• is related to: SOLR-5730 make Lucene's SortingMergePolicy and EarlyTerminatingSortingCollector configurable in Solr
• is related to: LUCENE-6766 Make index sorting a first-class citizen
• relates to: SOLR-16217 SortingMergePolicy: test coverage for dual-field sort
• links to: GitHub Pull Request #313