try to commit in case of failure which hopefully frees up some RAM

source/net/yacy/cora/federate/solr/connector/SolrServerConnector.java

@@ -181,7 +181,12 @@ public abstract class SolrServerConnector extends AbstractSolrConnector implemen
             try {
                 this.server.add(solrdoc, -1);
             } catch (Throwable ee) {
-                throw new IOException(ee);
+                try {
+                    this.server.commit();
+                    this.server.add(solrdoc, -1);
+                } catch (Throwable eee) {
+                    throw new IOException(eee);
+                }
             }
         }
     }