It's internal SQL Server query releated to index statistics.

>When I run the statement in SQL Analzyer
>delete from tmp_pl_acctinfo where jobperiod = "200701"
>I saw the unknow process in the trace window.
>what it?
>
>SELECT statman([JobPeriod],@PSTATMAN) FROM (SELECT TOP 100 PERCENT [JobPeriod] FROM [dbo].[tmp_pl_acctinfo] WITH(READUNCOMMITTED,SAMPLE 4.296323e+000 PERCENT) ORDER BY [JobPeriod]) AS _MS_UPDSTATS_TBL OPTION (BYPASS OPTIMIZER_QUEUE, MAXDOP 1)