May 31, 2015 at 11:20 pm
I am new to mssql server and i need some help. There is a table on one of my databases that occupies a lot of space. And the space usage is as follows: (all values in KB)
reserved: 42329064
data: 16272288
index: 26050032
unused: 6744
This table takes up almost 80% of my database size, and the information is this table just captures the time spent by a user on the website(not very critical data)
I would like to know how to delete the entire index (which is what is occupying most space) to free up disk space. the index is a clustered index.
can someone pl tell me the steps to achieve this? I am new to mssql and my knowledge is just limited to getting along with navigating thru the ssms
May 31, 2015 at 11:45 pm
What is the structure of this table. which columns you are using for the clustered index. (Share the table schema of the table)
How offend you use this data in your application?
How much data do u have in this table. means number of rows? if the table is huge ever have some though about partitioning the table? or purging this table?
Drop or deleting the clustered index not not help you unless you really know what you are doing.
June 1, 2015 at 2:23 am
The clustered index is the table, so deleting it won't help you.
If the data isn't important, how about archiving or deleting old data?
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
June 2, 2015 at 10:32 am
To evaluate this, we will need considerably more info about the table and its indexes. Please copy the code below into a "New Query..." window in SSMS, change the db and table name (in the bolded lines of the script with !), and then run it. Sorry, I know that it's a complicated script. But don't worry about that -- just change the names and click F5 (run). Post all of the results back here.
USE [<your_db_name_here>] --!naturally make sure you are in the right db
SET DEADLOCK_PRIORITY LOW --probably irrelevant, but just in case
DECLARE @list_missing_indexes bit
DECLARE @table_name sysname
--NOTE: showing missing indexes can take some time; set to 0 if you don't want to wait.
SET @list_missing_indexes = 1
SET @table_name = 'dbs' --<<-- !your table name goes here!
--SET @table_name = '%' --all tables
SELECT * FROM sys.dm_db_index_physical_stats ( DB_ID(), OBJECT_ID(@table_name), NULL, NULL, 'LIMITED')
PRINT 'Started @ ' + CONVERT(varchar(30), GETDATE(), 120)
IF @list_missing_indexes = 1
BEGIN
SELECT
GETDATE() AS capture_date,
DB_NAME(mid.database_id) AS Db_Name,
dps.row_count,
OBJECT_NAME(mid.object_id /*, mid.database_id*/) AS Table_Name,
mid.equality_columns, mid.inequality_columns, mid.included_columns,
user_seeks, user_scans, ca1.max_days_active, unique_compiles,
last_user_seek, last_user_scan, avg_total_user_cost, avg_user_impact,
system_seeks, system_scans, last_system_seek, last_system_scan, avg_total_system_cost, avg_system_impact,
mid.statement, mid.object_id, mid.index_handle
FROM sys.dm_db_missing_index_details mid WITH (NOLOCK)
CROSS APPLY (
SELECT DATEDIFF(DAY, create_date, GETDATE()) AS max_days_active FROM sys.databases WHERE name = 'tempdb'
) AS ca1
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
LEFT OUTER JOIN sys.dm_db_partition_stats dps WITH (NOLOCK) ON
dps.object_id = mid.object_id AND
dps.index_id IN (0, 1)
--order by
--DB_NAME, Table_Name, equality_columns
WHERE
1 = 1
AND mid.database_id = DB_ID() --only current db
AND OBJECT_NAME(mid.object_id) LIKE @table_name
--AND mid.object_id IN (OBJECT_ID('<table_name_1>'), OBJECT_ID('<table_name_2>'))
ORDER BY
--avg_total_user_cost * (user_seeks + user_scans) DESC,
Db_Name, Table_Name, equality_columns, inequality_columns
END --IF
PRINT 'Midpoint @ ' + CONVERT(varchar(30), GETDATE(), 120)
-- list index usage stats (seeks, scans, etc.)
SELECT
ius2.row_num, DB_NAME() AS db_name,
CASE WHEN i.name LIKE ca2.table_name + '%'
THEN '~' + SUBSTRING(i.name, LEN(ca2.table_name) + 1, 200)
ELSE i.name END AS index_name,
CASE WHEN i.is_unique = 0 THEN 'N' ELSE 'Y' END + '.' +
CASE WHEN i.is_primary_key = 0 AND i.is_unique_constraint = 0 THEN 'N' ELSE 'Y' END AS [uniq?],
ca2.table_name,
i.index_id, --ius.user_seeks + ius.user_scans AS total_reads,
dps.row_count,
SUBSTRING(key_cols, 3, 8000) AS key_cols, SUBSTRING(nonkey_cols, 3, 8000) AS nonkey_cols,
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,
fk.Reference_Count AS fk_ref_count,
DATEDIFF(DAY, CASE WHEN o.create_date > ca1.sql_startup_date THEN o.create_date
ELSE ca1.sql_startup_date END, GETDATE()) AS max_days_active,
FILEGROUP_NAME(i.data_space_id) AS filegroup_name,
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
CROSS JOIN (
SELECT create_date AS sql_startup_date FROM sys.databases WHERE name = 'tempdb'
) AS ca1
CROSS APPLY (
SELECT OBJECT_NAME(i.object_id/*, DB_ID()*/) AS table_name
) AS ca2
OUTER APPLY (
SELECT
', ' + COL_NAME(object_id, ic.column_id)
FROM sys.index_columns ic
WHERE
ic.key_ordinal > 0 AND
ic.object_id = i.object_id AND
ic.index_id = i.index_id
ORDER BY
ic.key_ordinal
FOR XML PATH('')
) AS key_cols (key_cols)
OUTER APPLY (
SELECT
', ' + COL_NAME(object_id, ic.column_id)
FROM sys.index_columns ic
WHERE
ic.key_ordinal = 0 AND
ic.object_id = i.object_id AND
ic.index_id = i.index_id
ORDER BY
COL_NAME(object_id, ic.column_id)
FOR XML PATH('')
) AS nonkey_cols (nonkey_cols)
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 /* AND
o.name NOT LIKE 'dtprop%' AND
o.name NOT LIKE 'filestream[_]' AND
o.name NOT LIKE 'MSpeer%' AND
o.name NOT LIKE 'MSpub%' AND
--o.name NOT LIKE 'queue[_]%' AND
o.name NOT LIKE 'sys%' */
)
--AND OBJECT_NAME(i.object_id /*, DB_ID()*/) IN ('tbl1', 'tbl2', 'tbl3')
ORDER BY
--row_count DESC,
--ius.user_scans DESC,
--ius2.row_num, --user_scans&|user_seeks
db_name, table_name,
-- list clustered index first, if any, then other index(es)
CASE WHEN i.index_id IN (0, 1) THEN 1 ELSE 2 END,
key_cols
PRINT 'Ended @ ' + CONVERT(varchar(30), GETDATE(), 120)
SET DEADLOCK_PRIORITY NORMAL
SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".
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