Known Issues in Apache Solr

Learn about the known issues in Apache Solr, the impact or changes to the functionality, and the workaround.

Apache Tika upgrade may break morphlines indexing
The upgrade of Apache Tika from 1.27 to 2.3.0 brought potentially breaking changes for morphlines indexing. Duplicate/triplicate keys names were removed and certain parser class names were changed (For example, org.apache.tika.parser.jpeg.JpegParser changed to org.apache.tika.parser.image.JpegParser).
To avoid morphline commands failing after the upgrade, do the following:
  • Check if key name changes affect your morphlines. For more information, see Removed duplicate/triplicate keys in Migrating to Tika 2.0.0.
  • Check if the name of any parser you use has changed. For more information, see the Apache Tika API documentation.
Update your morphlines if necessary.
CDPD-28006: Solr access via Knox fails with impersonation error though auth_to_local and proxy user configs are set
Currently the names of system users which are impersonating users with Solr should match with the names of their respective Kerberos principals.
If, for some reason, this is not feasible, you must add the user name you want to associate with the custom Kerberos principal to Solr configuration via the Solr Service Environment Advanced Configuration Snippet (Safety Valve) environment variable in Cloudera Manager.

For more information, see Configuring custom Kerberos principals and custom system users.

CDH-77598: Indexing fails with socketTimeout

Starting from CDH 6.0, the HTTP client library used by Solr has a default socket timeout of 10 minutes. Because of this, if a single request sent from an indexer executor to Solr takes more than 10 minutes to be serviced, the indexing process fails with a timeout error.

This timeout has been raised to 24 hours. Nevertheless, there still may be use cases where even this extended timeout period proves insufficient.

If your MapreduceIndexerTool or HBaseMapreduceIndexerTool batch indexing jobs fail with a timeout error during the go-live (Live merge, MERGEINDEXES) phase (This means the merge takes longer than 24 hours).

Use the --go-live-timeout option where the timeout can be specified in milliseconds.

CDPD-12450: CrunchIndexerTool Indexing fails with socketTimeout
The http client library uses a socket timeout of 10 minutes. The Spark Crunch Indexer does not override this value, and in case a single batch takes more than 10 minutes, the entire indexing job fails. This can happen especially if the morphlines contain DeleteByQuery requests.
Try the following workarounds:
  • Check the batch size of your indexing job. Sending too large batches to Solr might increase the time needed on the Solr server to process the incoming batch.
  • If your indexing job uses deleteByQuery requests, consider using deleteById wherever possible as deleteByQuery involves a complex locking mechanism on the Solr side which makes processing the requests slower.
  • Check the number of executors for your Spark Crunch Indexer job. Too many executors can overload the Solr service. You can configure the number of executors by using the --mappers parameter
  • Check that your Solr installation is correctly sized to accommodate the indexing load, making sure that the number of Solr servers and the number of shards in your target collection are adequate.
  • The socket timeout for the connection can be configured in the morphline file. Add the solrClientSocketTimeout parameter to the solrLocator command

    Example

    SOLR_LOCATOR :
    { 
      collection : test_collection 
      zkHost : "zookeeper1.example.corp:2181/solr" 
    # 10 minutes in milliseconds 
      solrClientSocketTimeout: 600000  
      # Max number of documents to pass per RPC from morphline to Solr Server
      # batchSize : 10000
    
    }
    
CDPD-29289: HBaseMapReduceIndexerTool fails with socketTimeout
The http client library uses a socket timeout of 10 minutes. The HBase Indexer does not override this value, and in case a single batch takes more than 10 minutes, the entire indexing job fails.
You can overwrite the default 600000 millisecond (10 minute) socket timeout in HBase indexer using the --solr-client-socket-timeout optional argument for the direct writing mode (when the value of the --reducers optional argument is set to 0 and mappers directly send the data to the live Solr).
CDPD-20577: Splitshard operation on HDFS index checks local filesystem and fails

When performing a shard split on an index that is stored on HDFS, SplitShardCmd still evaluates free disk space on the local file system of the server where Solr is installed. This may cause the command to fail, perceiving that there is no adequate disk space to perform the shard split.

Run the following command to skip the check for sufficient disk space altogether:
  • On nonsecure clusters:
    curl 'http://$[***SOLR_SERVER_HOSTNAME***]:8983/solr/admin/collections?action=SPLITSHARD&collection=[***COLLECTION_NAME***]&shard=[***SHARD_TO_SPLIT***]&skipFreeSpaceCheck=true'
  • On secure clusters:
    curl -k -u : --negotiate 'http://$[***SOLR_SERVER_HOSTNAME***]:8985/solr/admin/collections?action=SPLITSHARD&collection=[***COLLECTION_NAME***]&shard=[***SHARD_TO_SPLIT***]&skipFreeSpaceCheck=true'

Replace [***SOLR_SERVER_HOSTNAME***] with a valid Solr server hostname, [***COLLECTION_NAME***] with the collection name, and [***SHARD_TO_SPLIT***] with the ID of the to split.

To verify that the command executed succesfully, check overseer logs for a similar entry:

2021-02-02 12:43:23.743 INFO  (OverseerThreadFactory-9-thread-5-processing-n:myhost.example.com:8983_solr) [c:example s:shard1  ] o.a.s.c.a.c.SplitShardCmd Skipping check for sufficient disk space
DOCS-5717: Lucene index handling limitation
The Lucene index can only be upgraded by one major version. Solr 8 will not open an index that was created with Solr 6 or earlier.
None, you need to reindex collections.
CDH-22190: CrunchIndexerTool which includes Spark indexer requires specific input file format specifications
If the --input-file-format option is specified with CrunchIndexerTool, then its argument must be text, avro, or avroParquet, rather than a fully qualified class name.
None
CDH-26856: Field value class guessing and Automatic schema field addition are not supported with the MapReduceIndexerTool nor with the HBaseMapReduceIndexerTool
The MapReduceIndexerTool and the HBaseMapReduceIndexerTool can be used with a Managed Schema created via NRT indexing of documents or via the Solr Schema API. However, neither tool supports adding fields automatically to the schema during ingest.
Define the schema before running the MapReduceIndexerTool or HBaseMapReduceIndexerTool. In non-schemaless mode, define in the schema using the schema.xml file. In schemaless mode, either define the schema using the Solr Schema API or index sample documents using NRT indexing before invoking the tools. In either case, Cloudera recommends that you verify that the schema is what you expect, using the List Fields API command.
CDH-19407: The Browse and Spell Request Handlers are not enabled in schemaless mode
The Browse and Spell Request Handlers require certain fields to be present in the schema. Since those fields cannot be guaranteed to exist in a Schemaless setup, the Browse and Spell Request Handlers are not enabled by default.
If you require the Browse and Spell Request Handlers, add them to the solrconfig.xml configuration file. Generate a non-schemaless configuration to see the usual settings and modify the required fields to fit your schema.
CDH-17978: Enabling blockcache writing may result in unusable indexes
It is possible to create indexes with solr.hdfs.blockcache.write.enabled set to true. Such indexes may appear corrupt to readers, and reading these indexes may irrecoverably corrupt indexes. Blockcache writing is disabled by default.
None
CDH-58276: Users with insufficient Solr permissions may receive a "Page Loading" message from the Solr Web Admin UI
Users who are not authorized to use the Solr Admin UI are not given a page explaining that access is denied to them, instead receive a web page that never finishes loading.
None
CDH-15441: Using MapReduceIndexerTool or HBaseMapReduceIndexerTool multiple times may produce duplicate entries in a collection
Repeatedly running the MapReduceIndexerTool on the same set of input files can result in duplicate entries in the Solr collection. This occurs because the tool can only insert documents and cannot update or delete existing Solr documents. This issue does not apply to the HBaseMapReduceIndexerTool unless it is run with more than zero reducers.
To avoid this issue, use HBaseMapReduceIndexerTool with zero reducers.
CDH-58694: Deleting collections might fail if hosts are unavailable
It is possible to delete a collection when hosts that host some of the collection are unavailable. After such a deletion, if the previously unavailable hosts are brought back online, the deleted collection may be restored.
Ensure all hosts are online before deleting collections.
CDPD-13923: Every Configset is Untrusted Without Kerberos
Solr 8 introduces the concept of ‘untrusted configset’, denoting configsets that were uploaded without authentication. Collections created with an untrusted configset will not initialize if <lib> directives are used in the configset.
Select one of the following options if you would like to use untrusted configsets with <lib> directives:
  • If the configset contains external libraries, but you do not want to use them, simply upload the configsets after deleting the <lib> directives.

  • If the configset contains external libraries, and you want to use them, choose one from the following options:

    • Secure your cluster before reuploading the configset.

    • Add the libraries to Solr’s classpath, then reupload the configset without the <lib> directives.

Unsupported features

The following Solr features are currently not supported in Cloudera Data Platform:

Limitations

Default Solr core names cannot be changed
Although it is technically possible to give user-defined Solr core names during core creation, it is to be avoided in te context of Cloudera Search. Cloudera Manager expects core names in the default "collection_shardX_replicaY" format. Altering core names results in Cloudera Manager being unable to fetch Solr metrics for the given core and this, eventually, may corrupt data collection for co-located core, or even shard and server level charts.