Getting SharePoint crawl history

I have an application that uses the Microsoft.Office.Server.Search.Administration.CrawlHistory class to read crawl history information once a day and save it to a database where we can generate reports and statistics. For some reason, though, this 开发者_如何学Cclass will not return data for crawls that started on the current date; it will only return data for crawls that started on an earlier data. Can anyone explain how to get this class to return data for all crawls that have run?

1. Use .NET Reflector to see the source code of the CrawlHistory class (additionally, you may want to use the FileGenerator add-in).
2. Check the dbo.proc_MSS_GetCrawlHistory stored procedure from the SharedServicesInstanceName_Search_DB database (all GetCrawlHistory overloads use it internally).