Thursday, March 3, 2016

Know read and write ratio before you tune database performance

 SELECT object_name(s.object_id) as usertable,
       SUM(user_seeks + user_scans + user_lookups) as reads,
  SUM(user_updates) as writes,
  SUM(user_seeks + user_scans + user_lookups+user_updates)  as totalIO,

CASE
WHEN SUM(user_seeks + user_scans + user_lookups+user_updates) >0
then round(SUM(user_seeks + user_scans + user_lookups)*100/SUM(user_seeks + user_scans + user_lookups+user_updates),0)
else 0
END
AS readratio,
CASE
WHEN SUM(user_seeks + user_scans + user_lookups+user_updates) >0
then SUM(user_updates)*100/SUM(user_seeks + user_scans + user_lookups+user_updates)
else 0
END
AS writeratio
FROM sys.dm_db_index_usage_stats AS s
INNER JOIN sys.indexes AS i
ON s.object_id = i.object_id
AND i.index_id = s.index_id
WHERE objectproperty(s.object_id,'IsUserTable') = 1
--AND s.database_id = @dbid
--GROUP BY object_name(s.object_id)

GROUP BY s.object_id

--order by totalIO desc,readratio desc,reads desc,writeratio desc,writes desc

order by totalIO DESC, writes desc,writeratio desc

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