Use of “distrib=false” in Apache Solr

Apache Solr is a widely used search platform that allows users to store, index, and search large volumes of data efficiently. SolrCloud is a distributed version of Solr that helps in scalability and fault tolerance by distributing the index across multiple nodes in a cluster. Having said that, There is some use case, Where we need to disable query distribution. This is where the “distrib=false” parameter comes into play.

In Apache Solr, the parameter “distrib=false” is used to disable the distribution of a search query across multiple nodes in a SolrCloud cluster.

Use of "distrib=false" in Apache Solr

What is the “distrib=false” parameter?

The “distrib=false” can be added to a Solr query to disable query distribution in SolrCloud. By default, SolrCloud will distribute queries to all nodes in the cluster to achieve high availability and fault tolerance.

However, There are scenarios, Where you need to check a very specific Shard or replica is accessible or not. The use of “distrib=false” is basically to avoid the distribution of this query to the different replicas. It will fetch the data from the node, which is specified in the command.

For example:

curl -s --negotiate -u: "http://HOST1:<Port>/solr/collection_shard1_replica_n1/select?q=*:*&distrib=false"

In the above example, the “distrib=false” parameter is added to the query URL. Solr will execute the query on the specified node “HOST1”. Solr will respond to the client without involving other nodes in the cluster.

Conclusion

The “distrib=false” parameter is a useful feature of SolrCloud that allows you to disable query distribution for specific queries/use cases. By executing queries on a single node, you can reduce network overhead and test the performance of individual nodes in the cluster. However, it’s important to note that disabling query distribution can impact the fault tolerance and high availability of your SolrCloud cluster. Therefore, it’s important to use this parameter only when it’s necessary.

Good Luck with your Learning. Use comment for any questions or discussion

Related Topics:

How to Add or Delete Replicas in Solr Collection

Solr TTL – Auto-Purging Solr Documents

Deleting Documents in Apache Solr manually

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