How to speed up a SQL query which is using DISTINCT - sql

Question

From what I have read about this it seems like the best solution is to create an INDEX but I am not sure which columns I should be creating indexes for. This is my first time working with SQL indexes.
If I remove the DISTINCT call from this query I get over 1000 results in just over a second. However with the DISTINCT call it returns the results in 10 seconds (obviously without the duplicates).
If anyone has any alternative solutions I am all ears.
This is the query (the second SELECT is where the DISTINCT function is called):
SELECT
Sku,
Name,
ccp.Polygon,
MarketAvailability,
Coverage,
Range
FROM
(SELECT DISTINCT
dbo.CatalogEntry.CatalogEntryId as Id,
dbo.CatalogEntry.Code as Sku,
CoverageNode.Name as Coverage,
RangeNode.Name as [Range],
(SELECT CatalogContentProperty.LongString
FROM CatalogContentProperty
WHERE MetaFieldName = 'ItemChartName'
AND (CatalogContentProperty.LongString IS NOT NULL)
AND (CatalogContentProperty.ObjectId = dbo.CatalogEntry.CatalogEntryId)) AS [Name],
(SELECT CatalogContentProperty.LongString
FROM CatalogContentProperty
WHERE MetaFieldName = 'MarketAvailabilityDetailsCollection'
AND (CatalogContentProperty.LongString IS NOT NULL)
AND (CatalogContentProperty.ObjectId = dbo.CatalogEntry.CatalogEntryId)) AS MarketAvailability
FROM
dbo.CatalogEntry
INNER JOIN
dbo.NodeEntryRelation ON dbo.CatalogEntry.CatalogEntryId = dbo.NodeEntryRelation.CatalogEntryId
INNER JOIN
dbo.CatalogNode AS CoverageNode ON dbo.NodeEntryRelation.CatalogNodeId = CoverageNode.CatalogNodeId
INNER JOIN
dbo.CatalogNode AS RangeNode ON CoverageNode.ParentNodeId = RangeNode.CatalogNodeId
INNER JOIN
dbo.CatalogContentProperty ON dbo.CatalogEntry.CatalogEntryId = dbo.CatalogContentProperty.ObjectId
INNER JOIN
dbo.CatalogNode AS ModelNode ON RangeNode.ParentNodeId = ModelNode.CatalogNodeId
INNER JOIN
dbo.CatalogNode AS BrandNode ON ModelNode.ParentNodeId = BrandNode.CatalogNodeId
WHERE
(dbo.CatalogEntry.ClassTypeId = N'Variation') AND
(dbo.CatalogContentProperty.MetaFieldName = N'ItemIsChart') AND
RangeNode.Name != 'C-MAP' AND
(BrandNode.Name = '' OR '' = '' OR '' IS NULL) AND
(ModelNode.Name = '' OR '' = '' OR '' IS NULL) AND
(CoverageNode.Name = '' OR '' = '' OR '' IS NULL) AND
(RangeNode.Name = '' OR '' = '' OR '' IS NULL)
) AS CmapResults
INNER JOIN
(SELECT
GEOMETRY::STGeomFromText(CatalogContentProperty.LongString,4326) AS PolygonGeometry,
CatalogContentProperty.LongString AS Polygon,
CatalogContentProperty.ObjectId
FROM
CatalogContentProperty
WHERE
MetaFieldName = 'ItemChartCoordinates' AND
(CatalogContentProperty.LongString IS NOT NULL)) ccp ON ccp.ObjectId = CmapResults.Id
WHERE
((GEOGRAPHY::STGeomFromText(PolygonGeometry.MakeValid().STUnion(PolygonGeometry.MakeValid().STStartPoint()).STAsText(), 4326).STDistance(GEOGRAPHY::STGeomFromText('POINT(50.9835929 -1.4205852)', 4326)) / 1609.344) <= 100 OR 'POINT(50.9835929 -1.4205852)' IS NULL)
AND MarketAvailability IS NOT NULL
ORDER BY
GEOGRAPHY::STGeomFromText(PolygonGeometry.MakeValid().STUnion(PolygonGeometry.MakeValid().STStartPoint()).STAsText(), 4326).STArea() DESC;
I am using SQL Server Management Studio 2012. The aim is to get the query with the DISTINCT call to return in the same amount of time as the query would without the DISTINCT call.

Answer 1

Your query looks a bit complicated. Will this one produce the same output?
SELECT DISTINCT ce.Code as Sku
, max(case when ccp.MetaFieldName = 'ItemChartName' then ccp.LongString end) as 'Name'
, max(case when ccp.MetaFieldName = 'MarketAvailabilityDetailsCollection' then ccp.LongString end) as 'MarketAvailability'
, max(case when ccp.MetaFieldName = 'ItemChartCoordinates' then ccp.LongString end) as 'Polygon'
, CoverageNode.Name as Coverage
, RangeNode.Name as 'Range'
FROM dbo.CatalogEntry ce
INNER JOIN dbo.NodeEntryRelation ner ON ce.CatalogEntryId = ner.CatalogEntryId
INNER JOIN dbo.CatalogNode CoverageNode ON dbo.NodeEntryRelation.CatalogNodeId = CoverageNode.CatalogNodeId
INNER JOIN dbo.CatalogNode RangeNode ON CoverageNode.ParentNodeId = RangeNode.CatalogNodeId
INNER JOIN dbo.CatalogContentProperty ccp ON ce.CatalogEntryId = ccp.ObjectId
INNER JOIN dbo.CatalogNode ModelNode ON RangeNode.ParentNodeId = ModelNode.CatalogNodeId
INNER JOIN dbo.CatalogNode BrandNode ON ModelNode.ParentNodeId = BrandNode.CatalogNodeId
WHERE ce.ClassTypeId = N'Variation'
and ccp.MetaFieldName = N'ItemIsChart'
and RangeNode.Name != 'C-MAP'
--and (BrandNode.Name = '' OR '' = '' OR '' IS NULL) -- always true
--and (ModelNode.Name = '' OR '' = '' OR '' IS NULL) -- always true
--and (CoverageNode.Name = '' OR '' = '' OR '' IS NULL) -- always true
--and (RangeNode.Name = '' OR '' = '' OR '' IS NULL) -- always true
and (GEOGRAPHY::STGeomFromText(GEOMETRY::STGeomFromText(ccp.LongString,4326).MakeValid().STUnion(GEOMETRY::STGeomFromText(ccp.LongString,4326).MakeValid().STStartPoint()).STAsText(), 4326).STDistance(GEOGRAPHY::STGeomFromText('POINT(50.9835929 -1.4205852)', 4326)) / 1609.344) <= 100 -- OR 'POINT(50.9835929 -1.4205852)' IS NULL -- redundant
)
and max(case when ccp.MetaFieldName = 'MarketAvailabilityDetailsCollection' then ccp.LongString end)
ORDER BY GEOGRAPHY::STGeomFromText(GEOMETRY::STGeomFromText(ccp.LongString,4326).MakeValid().STUnion(GEOMETRY::STGeomFromText(ccp.LongString,4326).MakeValid().STStartPoint()).STAsText(), 4326).STArea() DESC;

Answer 2

So the answer is my case was to remove the DISTINCT and to do the duplicate removing using LINQ! Load times went from 10-11ish seconds to 4-5ish seconds