Lucene.Net.QueryParsers.Classic.ParseException

[mohit-naroliya]

Describe the bug

We encountered a strange issue on the production site that caused it to go down. After investigating, we found few exceptions in the log related to Lucene. Here are the logged exceptions:

OrchardCore.Search.Lucene.Services.LuceneSearchService|ERROR|Incorrect Lucene search query syntax provided in search. Lucene.Net.QueryParsers.Classic.ParseException: Cannot parse '"Find Your New Water Billing Account and Customer IDs': Lexical error at line 1, column 54.  Encountered: <EOF> after : "\"Find Your New Water Billing Account and Customer IDs"
---> Lucene.Net.QueryParsers.Classic.TokenMgrError: Lexical error at line 1, column 54.  Encountered: <EOF> after : "\"Find Your New Water Billing Account and Customer IDs"
   at Lucene.Net.QueryParsers.Classic.QueryParserTokenManager.GetNextToken()
   at Lucene.Net.QueryParsers.Classic.QueryParser.Jj_ntk()
   at Lucene.Net.QueryParsers.Classic.QueryParser.Modifiers()
   at Lucene.Net.QueryParsers.Classic.QueryParser.Query(String field)
   at Lucene.Net.QueryParsers.Classic.QueryParserBase.Parse(String query)
   --- End of inner exception stack trace ---
   at Lucene.Net.QueryParsers.Classic.QueryParserBase.Parse(String query)
   at OrchardCore.Search.Lucene.Services.LuceneSearchService.SearchAsync(String indexName, String term, Int32 start, Int32 size)    at Lucene.Net.QueryParsers.Classic.QueryParserBase.Parse(String query)
   at OrchardCore.Search.Lucene.Services.LuceneSearchService.SearchAsync(String indexName, String term, Int32 start, Int32 size)

Following the initial exception, we started receiving numerous connection failed exceptions, which ultimately caused the site to go down. Here is the log and the relevant exceptions:

Microsoft.AspNetCore.Server.IIS.Core.IISHttpServer|ERROR|Connection ID "16933534604013338735", Request ID "4000007b-0001-eb00-b63f-84710c7967bb": An unhandled exception was thrown by the application. System.InvalidOperationException: Timeout expired.  The timeout period elapsed prior to obtaining a connection from the pool.  This may have occurred because all pooled connections were in use and max pool size was reached.
   at Microsoft.Data.Common.ADP.ExceptionWithStackTrace(Exception e)
--- End of stack trace from previous location ---
   at OrchardCore.Queries.Sql.SqlQuerySource.ExecuteQueryAsync(Query query, IDictionary`2 parameters)
   at OrchardCore.Queries.Sql.SqlQuerySource.ExecuteQueryAsync(Query query, IDictionary`2 parameters)
   at OrchardCore.Queries.Liquid.QueryFilter.ProcessAsync(FluidValue input, FilterArguments arguments, LiquidTemplateContext ctx)
   at Fluid.Ast.FilterExpression.EvaluateAsync(TemplateContext context)
   at Fluid.Ast.AssignStatement.<WriteToAsync>g__Awaited|7_0(ValueTask`1 task, TemplateContext context, String identifier)
   at Fluid.Parser.FluidTemplate.Awaited(ValueTask`1 task, TextWriter writer, TextEncoder encoder, TemplateContext context, IReadOnlyList`1 statements, Int32 startIndex)
   at OrchardCore.DisplayManagement.Liquid.LiquidViewTemplateExtensions.RenderAsync(LiquidViewTemplate template, TextWriter writer, TextEncoder encoder, LiquidTemplateContext context, Object model)
   at OrchardCore.Liquid.Services.LiquidTemplateManager.RenderHtmlContentAsync(String source, TextEncoder encoder, Object model, IEnumerable`1 properties)
   at OrchardCore.Templates.Services.TemplatesShapeBindingResolver.<>c__DisplayClass8_0.<<BuildShapeBinding>b__0>d.MoveNext()

I went through the OC branch code base and found that there is a method opening a SQL Server connection without properly closing it. This could be the reason we are reaching the maximum connection pool size, leading to the site going down.

Above image method calling from the IndexingBackgroundTask that runs every minute.

Orchard Core version - 1.8.3

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[sebastienros]

How is the Lucene query issue related to the SQL connections pool limits? Can you share more of the stack-trace where the lucene issue is coming from? I want to understand what is sending user input as a lucene query. Because what is happening is that the code is expecting a lucene query, but the user doesn't provide that. There is a mismatch that needs to be resolved. If it's your code then don't expect a query from the user, build a query from the text that is provided. IF it's OC's code we need to fix it, but we need to know what is calling it.

The example you showed for the connection is actually closing it as it's using a using statement that will dispose and close the connection however it exits the method. It doesn't mean there is no such issue, but not in the code you pointed to.