Question

I had asked a question on stackoverflow:
Large SQL Server database timing out PHP web application

The problem was that the query was fast for when a previous date was chosen and slow for a more current date. We fixed it by recreating the index and hence it worked. For a while I thought the index might have gotten corrupted.

Today the issue occurred again (slow) and by recreating it again it ran fast. This was done on the date column which is of type datetime.

Is there a specific reason for this or is the SQL Server 2008 R2 corrupted?

Answer 1

try using UPDATE STATISTICS (Transact-SQL)

Updates query optimization statistics on a table or indexed view. By
default, the query optimizer already updates statistics as necessary
to improve the query plan; in some cases you can improve query
performance by using UPDATE STATISTICS or the stored procedure
sp_updatestats to update statistics more frequently than the default
updates.

UPDATE STATISTICS table_or_indexed_view_name 
    [ 
        { 
            { index_or_statistics__name }
          | ( { index_or_statistics_name } [ ,...n ] ) 
                }
    ] 
    [    WITH 
        [ 
            FULLSCAN 
            | SAMPLE number { PERCENT | ROWS } 
            | RESAMPLE 
            | <update_stats_stream_option> [ ,...n ]
        ] 
        [ [ , ] [ ALL | COLUMNS | INDEX ] 
        [ [ , ] NORECOMPUTE ] 
    ] ;

<update_stats_stream_option> ::=
    [ STATS_STREAM = stats_stream ]
    [ ROWCOUNT = numeric_constant ]
    [ PAGECOUNT = numeric_contant ]