SolrNet.Exceptions.SolrConnectionException: The operation has timed out

Question

After sitecore upgrade from 7.2 to 8.2u3 and solr from 5.4.1 to v6.1, below solr timeout starts to happen in one server, works fine in local machine setup. We have increased from 125500 (on local win10) to 200000 (on win2012 server). but that didn't help. Wonder what could be the root cause. Please advice.

Job started: Index_Update_IndexName=sitecore_master_index|#Exception: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> SolrNet.Exceptions.SolrConnectionException: The operation has timed out ---> System.Net.WebException: The operation has timed out at System.Net.HttpWebRequest.GetResponse() at HttpWebAdapters.Adapters.HttpWebRequestAdapter.GetResponse() at SolrNet.Impl.SolrConnection.GetResponse(IHttpWebRequest request) at SolrNet.Impl.SolrConnection.PostStream(String relativeUrl, String contentType, Stream content, IEnumerable1 parameters) --- End of inner exception stack trace --- at SolrNet.Impl.SolrConnection.PostStream(String relativeUrl, String contentType, Stream content, IEnumerable1 parameters) at SolrNet.Impl.SolrConnection.Post(String relativeUrl, String s) at SolrNet.Commands.OptimizeCommand.Execute(ISolrConnection connection) at SolrNet.Impl.SolrBasicServer1.SendAndParseHeader(ISolrCommand cmd) at SolrNet.Impl.SolrBasicServer1.Optimize(CommitOptions options) at Sitecore.ContentSearch.SolrProvider.SwitchOnRebuildSolrSearchIndex.PerformRebuild(Boolean resetIndex, Boolean optimizeOnComplete, IndexingOptions indexingOptions, CancellationToken cancellationToken) at Sitecore.ContentSearch.SolrProvider.SolrSearchIndex.Rebuild(Boolean resetIndex, Boolean optimizeOnComplete) --- End of inner exception stack trace --- at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor) at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) at System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters) at (Object , Object[] ) at Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args) at Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain) at Sitecore.Jobs.Job.ThreadEntry(Object state)

Answer 1

We had to increase the timeout further to 50000 to complete index rebuild. The timeout was caused by optimize command. It is the final step of index rebuild. After all items are already added to the index, an optimization command is sent to Solr server. It reduces size of the index and improves search speed.

<setting name="ContentSearch.Solr.ConnectionTimeout" value="500000" />

Answer 2

You may need to request a patch from Sitecore Support as this is a known issue. The Sitecore Patch number is #405677.

The same issue was raised on Sitecore Community here. You may find the patch at the following GitHub Repository but I would recommend to contact Sitecore Support directly and also provide them the details along with the IoC library you are using.