3289620 - Could Not Execute Search after solr version downgrade

Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental.

After a release was deployed, which was build with lower solr version than the one which was present in the release deployed previously, a solr collection is marked as “Down” in Solr Admin Console and one cannot execute search.

There are errors being logged like the following, pointing to issues with solr core:

org.apache.solr.common.SolrException: Error opening new searcher

org.apache.lucene.index.IndexFormatTooNewException: Format version is not supported (resource BufferedChecksumIndexInput(MMapIndexInput(path="/var/solr/master_backoffice_backoffice_product_flip_shard1_replica_n1/data/index/segments_2"))): 10 (needs to be between 7 and 9)

o.a.s.c.CoreContainer Error waiting for SolrCore to be loaded on startup => org.apache.solr.common.SolrException: Unable to create core [master_backoffice_backoffice_product_flip_shard1_replica_n1]

Reindexing of collection fails with errors pointing to solr core being in “Down” state:

"Could not export configuration for index: name=master_backoffice_backoffice_product_flip","name":"de.hybris.platform.solrfacetsearch.solr.exceptions.SolrServiceException","cause":{"commonElementCount":30,"localizedMessage":"Could not find a healthy node to handle the request."

SAP Commerce Cloud

solr downgrade, format not supported , KBA , CEC-SCC-COM-SRC-SER , Search and Navigation , Problem