Fixed Issues in Apache Solr

Review the list of Apache Solr issues that are resolved in Cloudera Runtime 7.1.8.

CDPD-29853: Solr 8 now works in secure environments without sending OPTIONS requests during internal communication

This fix eliminates unnecessary OPTIONS requests in internal Solr communication, improving performance.

CDPD-26082: MapreduceIndexerTool performance problem in CDP

The handling of HDFS caching in MRIT has changed to mitigate this known issue. Before the fix, the solr.hdfs.blockcache.enabled setting was always forced to be false and could not be overridden. After the fix, it becomes possible to control this setting using the solr.hdfs.blockcache.enabled property and its default value has also been changed to true.

This has a few consequences that may affect existing systems:

• MRIT starts to use HDFS caching by default, which may slightly increase memory usage.
• It is possible now to control HDFS caching. For more information, see Solr and HDFS - the block cache in Tuning Cloudera Search.

CDPD-24704: Checksum failed during MRIT MERGEINDEXES

In certain rare cases, the reuse of the results directory before MERGEINDEXES calls caused checksum failure in MRIT, with the following error message:

Caused by: org.apache.lucene.index.CorruptIndexException: checksum failed (hardware
      problem?)

After the fix, the index is moved to a unique directory before calling MERGEINDEXES. After the call finishes, the index directory is renamed back to its original name.

CDPD-23110: Hiveserver2/HMS hung because of the LeaseRenewer thread is waiting to get the kerberos ticket via System.in

Solr client does not overwrite ‘null’ value of javax.security.auth.useSubjectCredsOnly parameter, it only throws a warning during connection setup:

System Property: javax.security.auth.useSubjectCredsOnly set to: [true|null] not false.  
SPNego authentication may not be successful.

This may cause issues when connecting Solr to custom applications. To prevent this, you need to set

-D javax.security.auth.useSubjectCredsOnly=false

in the JVM configuration of those applications. Cloudera has implemented this change in MapReduceIndexer, CrunchIndexer, Spark-Solr, Hive-Solr connector, and Atlas.

CDPD-28879: Solr sets the Strict Transport Security policy in the web server responses when TLS is enabled.