[SOLR-5679] Shard splitting fails with ClassCastException on clusterstate.json with router as string

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.6, 4.6.1
• Fix Version/s: 4.7
• Component/s: SolrCloud
• Assignee: Shalin Shekhar Mangar
• Reporter: Shalin Shekhar Mangar
• Created: 30/Jan/14 14:08
• Updated: 02/Oct/19 17:24
• Resolved: 30/Jan/14 16:10

Description

SOLR-5246 added support for splitting collections configured with a router.field but the fix was not back-compatible.

After upgrading an old SolrCloud cluster to 4.6 or 4.6.1, shard splitting can fail with the following message:

ERROR o.a.s.handler.admin.CoreAdminHandler - ERROR executing split:
java.lang.ClassCastException: java.lang.String cannot be cast to java.util.Map
at org.apache.solr.handler.admin.CoreAdminHandler.handleSplitAction(CoreAdminHandler.java:285) [solr-core-4.6.1.jar:4.6.1 1560866 - mark - 2014-01-23 20:21:50]
at org.apache.solr.handler.admin.CoreAdminHandler.handleRequestBody(CoreAdminHandler.java:193) [solr-core-4.6.1.jar:4.6.1 1560866 - mark - 2014-01-23 20:21:50]
at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:135) [solr-core-4.6.1.jar:4.6.1 1560866 - mark - 2014-01-23 20:21:50]

This happens because the cluster state still contains the router as a string. The clusterstate.json is supposed to auto-upgrade if cluster state is upgraded but according to the user report that did not happen. In any case, we need to fix the core admin split.