kapil_kk (12/14/2013)
ScottPletcher (12/13/2013)
I suggest making index changes scripted below, following these steps:1) Capture and save the existing index missing/usage stats for that table immediately, before any hanges are made.
2) Run the code to make index changes; the code may run a while, depending on the table size.
3) Allow some time for table activity, then re-capture the index missing/usage stats and compare to original.
DECLARE @list_missing_indexes bit
DECLARE @table_name_pattern sysname
SET @list_missing_indexes = 1
SET @table_name_pattern = 'Employee'
PRINT 'Started @ ' + CONVERT(varchar(30), GETDATE(), 120)
-- list missing index info
IF @list_missing_indexes = 1
BEGIN
SELECT
GETDATE() AS capture_date,
DB_NAME(mid.database_id) AS Db_Name,
OBJECT_NAME(mid.object_id /*, mid.database_id*/) AS Table_Name,
mid.equality_columns, mid.inequality_columns, mid.included_columns,
migs.*,
mid.statement, mid.object_id, mid.index_handle
FROM sys.dm_db_missing_index_details mid WITH (NOLOCK)
LEFT OUTER JOIN sys.dm_db_missing_index_groups mig WITH (NOLOCK) ON
mig.index_handle = mid.index_handle
LEFT OUTER JOIN sys.dm_db_missing_index_group_stats migs WITH (NOLOCK) ON
migs.group_handle = mig.index_group_handle
--order by
--DB_NAME, Table_Name, equality_columns
WHERE
1 = 1
AND mid.database_id = DB_ID()
AND OBJECT_NAME(mid.object_id) LIKE @table_name_pattern
ORDER BY
--avg_total_user_cost * (user_seeks + user_scans) DESC,
Db_Name, Table_Name, equality_columns, inequality_columns
END --IF
-- list index usage stats (seeks, scans, etc.)
SELECT
ius2.row_num, DB_NAME() AS db_name, OBJECT_NAME(i.object_id/*, DB_ID()*/) AS table_name, i.name AS index_name,
FILEGROUP_NAME(i.data_space_id) AS filegroup_name,
(SELECT DATEDIFF(DAY, create_date, GETDATE()) FROM sys.databases WHERE name = 'tempdb') AS sql_up_days,
dps.row_count,
fk.Reference_Count AS fk_ref_count,
ius.index_id, --ius.user_seeks + ius.user_scans AS total_reads,
ius.user_seeks, ius.user_scans, ius.user_lookups, ius.user_updates,
ius.last_user_seek, ius.last_user_scan, ius.last_user_lookup, ius.last_user_update,
ius.system_seeks, ius.system_scans, ius.system_lookups, ius.system_updates,
ius.last_system_seek, ius.last_system_scan, ius.last_system_lookup, ius.last_system_update
FROM sys.indexes i WITH (NOLOCK)
INNER JOIN sys.objects o WITH (NOLOCK) ON
o.object_id = i.object_id
LEFT OUTER JOIN sys.dm_db_partition_stats dps WITH (NOLOCK) ON
dps.object_id = i.object_id AND
dps.index_id = i.index_id
LEFT OUTER JOIN sys.dm_db_index_usage_stats ius WITH (NOLOCK) ON
ius.database_id = DB_ID() AND
ius.object_id = i.object_id AND
ius.index_id = i.index_id
LEFT OUTER JOIN (
SELECT
database_id, object_id, MAX(user_scans) AS user_scans,
ROW_NUMBER() OVER (ORDER BY MAX(user_scans) DESC) AS row_num --user_scans|user_seeks+user_scans
FROM sys.dm_db_index_usage_stats WITH (NOLOCK)
WHERE
database_id = DB_ID()
--AND index_id > 0
GROUP BY
database_id, object_id
) AS ius2 ON
ius2.database_id = DB_ID() AND
ius2.object_id = i.object_id
LEFT OUTER JOIN (
SELECT
referenced_object_id, COUNT(*) AS Reference_Count
FROM sys.foreign_keys
WHERE
is_disabled = 0
GROUP BY
referenced_object_id
) AS fk ON
fk.referenced_object_id = i.object_id
WHERE
i.object_id > 100 AND
i.is_hypothetical = 0 AND
i.type IN (0, 1, 2) AND
o.type NOT IN ( 'IF', 'IT', 'TF', 'TT' ) AND
(
o.name LIKE @table_name_pattern
)
ORDER BY
--row_count DESC,
--ius2.row_num, --user_scans&|user_seeks
-- list clustered index first, if any, then other index(es)
db_name, table_name, CASE WHEN i.index_id IN (0, 1) THEN 1 ELSE 2 END, index_name
PRINT 'Ended @ ' + CONVERT(varchar(30), GETDATE(), 120)
ALTER TABLE [dbo].[Employee] DROP CONSTRAINT [uq1_Employee];
ALTER TABLE [dbo].[Employee] DROP CONSTRAINT [PK_Employee];
ALTER TABLE [dbo].[Employee] ADD
CONSTRAINT [uq1_Employee] UNIQUE CLUSTERED
(
[InstanceId] ASC,
[SiteId] ASC,
[LocalEmployeeId] ASC
)WITH (ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 95) ON [PRIMARY]
ALTER TABLE [dbo].[Employee] ADD
CONSTRAINT [PK_Employee] PRIMARY KEY NONCLUSTERED
(
[EmployeeId] ASC
)WITH (ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 99) ON [PRIMARY]
Hey Scott,
Can you please explain me what this script will do ?
DO I need to drop indexes for whole database tables and need to run this script for every tables and recreate the indexes?
Those scripts are for the "Employee" table, the one you posted the table definition for.
A) Run script #1 first and save the results.
B) Then run script #2.
C) Then, after a few days, run script #1 again and save the results.
Then we can compare A to C and see if things have improved.
SQL DBA,SQL Server MVP(07, 08, 09) A socialist is someone who will give you the shirt off *someone else's* back.