how to remove RelationshipIndex schema

1、 delete relatioinshipindex schema
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RelationType key = ((RelationTypeIndex)index).getType();
if(key instanceof EdgeLabelVertex)
{
Iterator relationEdges = key.query().types(BaseLabel.SchemaDefinitionEdge).direction(Direction.OUT).edges().iterator();
while (relationEdges.hasNext()) {
JanusGraphEdge e = relationEdges.next();
JanusGraphSchemaVertex v = (JanusGraphSchemaVertex) e.inVertex();
//TODO
if (v != null && v.name().contains(indexName)) {
//remove the edge from index to index field
e.remove();
}
}
((EdgeLabelVertex)key).resetCache();
}
}

//remove index
indexVertex.remove();
indexVertex.resetCache();
schemaCache.expireSchemaElement(indexLongId);
mgmt.commit();

2、check relationshipIndex schema deleted or not
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ManagementSystem. getRelationIndex(RelationType type, String name)

3、throw exception
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Caused by: java.lang.IllegalArgumentException
at com.google.common.base.Preconditions.checkArgument(Preconditions.java:77)
at org.janusgraph.graphdb.database.management.RelationTypeIndexWrapper.(RelationTypeIndexWrapper.java:36)
at org.janusgraph.graphdb.database.management.ManagementSystem$2.apply(ManagementSystem.java:402)
at org.janusgraph.graphdb.database.management.ManagementSystem$2.apply(ManagementSystem.java:398)
at com.google.common.collect.Iterators$8.transform(Iterators.java:794)
at com.google.common.collect.TransformedIterator.next(TransformedIterator.java:48)
at org.visallo.web.routes.graphbase.graphindex.GraphBaseIndexList.handle(GraphBaseIndexList.java:102)

Start by tracing ManagementSystem.getRelationIndex(RelationType type, String name) and RelationTypeIndexWrapper.java:36, using the reported ManagementSystem stack frames as the entry point. Check how relationship-index schema deletion is represented and why the wrapper rejects the remaining schema. Done means deletion can be verified through getRelationIndex without the reported IllegalArgumentException.

Written by the indexing model from the issue text.