Hej,
Databasobjektstatistik bör vara uppdaterad för att fatta rätt beslut av SQL Server Optimizer.
Om databasobjektstatistiken inte är uppdaterad kommer SQL Server-databasoptimeraren att fatta ett felaktigt beslut för genomförandeplanen för transaktionen.
Du kan kontrollera all statistik över databasobjekt med följande fråga.
SELECT
object_name(si.[object_id]) AS [TableName]
, CASE
WHEN si.[stats_id] = 0 then 'Heap'
WHEN si.[stats_id] = 1 then 'CL'
WHEN INDEXPROPERTY ( si.[object_id], si.[name], 'IsAutoStatistics') = 1 THEN 'Stats-Auto'
WHEN INDEXPROPERTY ( si.[object_id], si.[name], 'IsHypothetical') = 1 THEN 'Stats-HIND'
WHEN INDEXPROPERTY ( si.[object_id], si.[name], 'IsStatistics') = 1 THEN 'Stats-User'
WHEN si.[stats_id] BETWEEN 2 AND 1004 THEN 'NC ' + RIGHT('00' + convert(varchar, si.[stats_id]), 3)
ELSE 'Text/Image'
END AS [IndexType]
, si.[name] AS [IndexName]
, si.[stats_id] AS [IndexID]
, CASE
WHEN si.[stats_id] BETWEEN 1 AND 250 AND STATS_DATE (si.[object_id], si.[stats_id]) < DATEADD(m, -1, getdate())
THEN '!! More than a month OLD !!'
WHEN si.[stats_id] BETWEEN 1 AND 250 AND STATS_DATE (si.[object_id], si.[stats_id]) < DATEADD(wk, -1, getdate())
THEN '! Within the past month !'
WHEN si.[stats_id] BETWEEN 1 AND 250 THEN 'Stats recent'
ELSE ''
END AS [Warning]
, STATS_DATE (si.[object_id], si.[stats_id]) AS [Last Stats Update]
, no_recompute
FROM sys.stats AS si
WHERE OBJECTPROPERTY(si.[object_id], 'IsUserTable') = 1 and STATS_DATE (si.[object_id], si.[stats_id]) is not null
AND (INDEXPROPERTY ( si.[object_id], si.[name], 'IsAutoStatistics') = 1
OR INDEXPROPERTY ( si.[object_id], si.[name], 'IsHypothetical') = 1
OR INDEXPROPERTY ( si.[object_id], si.[name], 'IsStatistics') = 1)
ORDER BY [Last Stats Update]
go