Description

When using Solr as a search provider in Sitecore, various issues may appear under the following conditions:

• The Http Cache used by Sitecore for caching Solr responses is enabled - the ContentSearch.Solr.EnableHttpCache setting value is set to true.
• More than one Solr core is used for the search indexes. 

The issue descriptions as well as the solution can be found below.

Sitecore IGNORES MUlTI-Core Configuration

In case of using Solr 4.3 or earlier with the Unity IoC container, indexed items might be pushed to a single core (the default core) regardless of the configuration.

Sitecore May Not Start With Unity, Ninject And StructureMap

When using Solr 4.3.1 or later with the Unity, Ninject or ScturctureMap IoC containers Sitecore may fail to start and the following errors can be observed in the log files:

Ninject error:

Error activating ISolrConnection
More than one matching bindings are available.
Activation path:
 1) Request for ISolrConnection
Suggestions:
 1) Ensure that you have defined a binding for ISolrConnection only once.

StructureMap error:

StructureMap Exception Code:  202
No Default Instance defined for PluginFamily SolrNet.ISolrConnection, SolrNet, Version=0.4.0.2002, Culture=neutral, PublicKeyToken=null

Unity error:

Connection error to search provider [Solr] : Unable to connect to [http://localhost:55555/solr]

Solution

There are two possible options to resolve the issue:

• Change the IoC container to the Autofac or Castle Windsor.
• Disable the Http Cache by setting the ContentSearch.Solr.EnableHttpCache setting value to false.