[SOLR-15830] Concurrent core reloads mess up commits when using Schema API

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 9.1
• Assignee: Andras Salamon
• Reporter: Bence Szabó
• Created: 03/Dec/21 13:58
• Updated: 10/Jan/23 20:45
• Resolved: 27/Apr/22 12:58

Description

When using Schema API SchemaManager class triggers a core reload here: https://github.com/apache/solr/blob/cfc953b6b906ef742bba57024d327fbde5d564c2/solr/core/src/java/org/apache/solr/schema/SchemaManager.java#L132

As I understand this was introduced in SOLR-9832 and is useful to avoid accidentally reloading to an older version of the config. The problem is that in the solr core a listener is implemented to initiate a reload whenever a config change happens in ZK, this can be found here: https://github.com/apache/solr/blob/cfc953b6b906ef742bba57024d327fbde5d564c2/solr/core/src/java/org/apache/solr/core/SolrCore.java#L3140

When updating the schema using the Schema API both of these reloads get triggered and this can result a strange bug, where not all the indexed documents are visible if the indexing is started just after the schema API returned.

Issue Links

• is related to: SOLR-16174 Modernize TestBulkSchemaConcurrent
• links to: GitHub Pull Request #462