An unrecoverable error has occurred. Throwable occurred: org.apache.solr.common.SolrException when di-buildindex utility failed

di-buildindex utility failed due to this Error (An unrecoverable error has occurred. Throwable occurred: org.apache.solr.common.SolrException)

di-buildindex process is failed because of below error then follow these steps to resolve. This Error would be happen when more data is loaded.

Error :
INFO: Data import process was unsuccessful. An unrecoverable error has occurred.
Throwable occurred: org.apache.solr.common.SolrException: /MC_10001_CatalogEntry_en_US/dataimport Indexing failed

        at com.ibm.commerce.foundation.dataimport.process.util.SolrUtil.makeDataImportCommand(SolrUtil.java:242)
        at com.ibm.commerce.foundation.dataimport.process.DataImportProcessorMain.fullDataImport(DataImportProcessorMain.java:1503)
        at com.ibm.commerce.foundation.dataimport.process.DataImportProcessorMain.executeDIH(DataImportProcessorMain.java:789)
        at com.ibm.commerce.foundation.dataimport.process.DataImportProcessorMain.main(DataImportProcessorMain.java:349)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:48)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:600)
        at com.ibm.ws.bootstrap.WSLauncher.main(WSLauncher.java:267)
Feb 16, 2016 6:11:17 PM com.ibm.commerce.foundation.dataimport.util.DataImportHelper printException

==>Problem : This error is related to memory (<ramBufferSizeMB>32</ramBufferSizeMB>) which is configured in solrconfig.xml file in solr home.
File location ;
1 ./app/IBM/WebSphere/CommerceServer70/instances/instances_name/search/solr/home/MC_10001/en_US/CatalogEntry/unstructured/conf /solrconfig.xml
2. /app/IBM/WebSphere/CommerceServer70/instances/instances_name/search/solr/home/MC_10001/en_US/CatalogEntry/conf/solrconfig.xml
3. app/IBM/WebSphere/CommerceServer70/instances/instances_name/search/solr/home/MC_10001/en_US/CatalogGroup/conf/solrconfig.xml

==>Solution : Open these three files and find the ramBufferSize tag  (<ramBufferSizeMB>32</ramBufferSizeMB>) then update it up to 1GB (64MB, 128MB..etc) based on your environment setup.
2. Then run di-buildindex utility again.

Reference url ;
https://www-01.ibm.com/support/knowledgecenter/SSZLC2_7.0.0/com.ibm.commerce.developer.doc/refs/rsdsearchtroubleshootingindexoom.htm
https://www-01.ibm.com/support/knowledgecenter/SSZLC2_7.0.0/com.ibm.commerce.developer.doc/concepts/csdsearchperf.htm?lang=en