The following query will provide you missing indexes on Azure SQL Database. Do not run the query on the master, but on each user database. The following scripts do not apply on Azure Synapse.
SELECT CONVERT (varchar, getdate(), 126) AS runtime,
mig.index_group_handle,
mid.index_handle,
CONVERT (decimal (28,1),
migs.avg_total_user_cost *
migs.avg_user_impact *
(migs.user_seeks + migs.user_scans))
AS improvement_measure,
'CREATE INDEX missing_index_' +
CONVERT (varchar, mig.index_group_handle) +
'_' +
CONVERT (varchar, mid.index_handle) +
' ON ' +
mid.statement +
' (' + ISNULL (mid.equality_columns,'') +
CASE WHEN mid.equality_columns IS NOT NULL
AND mid.inequality_columns IS NOT NULL
THEN ','
ELSE ''
END + ISNULL (mid.inequality_columns, '') +
')' +
ISNULL (' INCLUDE (' + mid.included_columns + ')',
'') AS create_index_statement,
migs.*,
mid.database_id, mid.[object_id]
FROM sys.dm_db_missing_index_groups mig
INNER JOIN sys.dm_db_missing_index_group_stats migs
ON migs.group_handle = mig.index_group_handle
INNER JOIN sys.dm_db_missing_index_details mid
ON mig.index_handle = mid.index_handle
WHERE CONVERT (decimal (28,1),
migs.avg_total_user_cost *
migs.avg_user_impact *
(migs.user_seeks + migs.user_scans)) > 10
ORDER BY migs.avg_total_user_cost *
migs.avg_user_impact *
(migs.user_seeks + migs.user_scans) DESC
To find duplicated indexes, please execute the following query:
;WITH CTE_INDEX_DATA AS (
SELECT
SCHEMA_DATA.name AS schema_name,
TABLE_DATA.name AS table_name,
INDEX_DATA.name AS index_name,
STUFF((SELECT ', ' + COLUMN_DATA_KEY_COLS.name + ' ' + CASE WHEN INDEX_COLUMN_DATA_KEY_COLS.is_descending_key = 1 THEN 'DESC' ELSE 'ASC' END -- Include column order (ASC / DESC)
FROM sys.tables AS T
INNER JOIN sys.indexes INDEX_DATA_KEY_COLS
ON T.object_id = INDEX_DATA_KEY_COLS.object_id
INNER JOIN sys.index_columns INDEX_COLUMN_DATA_KEY_COLS
ON INDEX_DATA_KEY_COLS.object_id = INDEX_COLUMN_DATA_KEY_COLS.object_id
AND INDEX_DATA_KEY_COLS.index_id = INDEX_COLUMN_DATA_KEY_COLS.index_id
INNER JOIN sys.columns COLUMN_DATA_KEY_COLS
ON T.object_id = COLUMN_DATA_KEY_COLS.object_id
AND INDEX_COLUMN_DATA_KEY_COLS.column_id = COLUMN_DATA_KEY_COLS.column_id
WHERE INDEX_DATA.object_id = INDEX_DATA_KEY_COLS.object_id
AND INDEX_DATA.index_id = INDEX_DATA_KEY_COLS.index_id
AND INDEX_COLUMN_DATA_KEY_COLS.is_included_column = 0
ORDER BY INDEX_COLUMN_DATA_KEY_COLS.key_ordinal
FOR XML PATH('')), 1, 2, '') AS key_column_list ,
STUFF(( SELECT ', ' + COLUMN_DATA_INC_COLS.name
FROM sys.tables AS T
INNER JOIN sys.indexes INDEX_DATA_INC_COLS
ON T.object_id = INDEX_DATA_INC_COLS.object_id
INNER JOIN sys.index_columns INDEX_COLUMN_DATA_INC_COLS
ON INDEX_DATA_INC_COLS.object_id = INDEX_COLUMN_DATA_INC_COLS.object_id
AND INDEX_DATA_INC_COLS.index_id = INDEX_COLUMN_DATA_INC_COLS.index_id
INNER JOIN sys.columns COLUMN_DATA_INC_COLS
ON T.object_id = COLUMN_DATA_INC_COLS.object_id
AND INDEX_COLUMN_DATA_INC_COLS.column_id = COLUMN_DATA_INC_COLS.column_id
WHERE INDEX_DATA.object_id = INDEX_DATA_INC_COLS.object_id
AND INDEX_DATA.index_id = INDEX_DATA_INC_COLS.index_id
AND INDEX_COLUMN_DATA_INC_COLS.is_included_column = 1
ORDER BY INDEX_COLUMN_DATA_INC_COLS.key_ordinal
FOR XML PATH('')), 1, 2, '') AS include_column_list,
INDEX_DATA.is_disabled -- Check if index is disabled before determining which dupe to drop (if applicable)
FROM sys.indexes INDEX_DATA
INNER JOIN sys.tables TABLE_DATA
ON TABLE_DATA.object_id = INDEX_DATA.object_id
INNER JOIN sys.schemas SCHEMA_DATA
ON SCHEMA_DATA.schema_id = TABLE_DATA.schema_id
WHERE TABLE_DATA.is_ms_shipped = 0
AND INDEX_DATA.type_desc IN ('NONCLUSTERED', 'CLUSTERED')
)
SELECT
*
FROM CTE_INDEX_DATA DUPE1
WHERE EXISTS
(SELECT * FROM CTE_INDEX_DATA DUPE2
WHERE DUPE1.schema_name = DUPE2.schema_name
AND DUPE1.table_name = DUPE2.table_name
AND (DUPE1.key_column_list LIKE LEFT(DUPE2.key_column_list, LEN(DUPE1.key_column_list)) OR DUPE2.key_column_list LIKE LEFT(DUPE1.key_column_list, LEN(DUPE2.key_column_list)))
AND DUPE1.index_name <> DUPE2.index_name)