Key Lookup(Clustered)

Question

Key Lookup(Clustered)

liushka87

SSC Journeyman

Points: 90
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February 2, 2012 at 10:10 am

#256177

Hi everyone! Help me plz with a problem
In my query I join one table with another large table (about 194100 rows).I looked execution plan Cost:55 % Key Lookup(Clustered) took that join.
What can i do to resolve this problem? The query excecuted about 4 minutes

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Gail Shaw SSC Guru Points: 1004504 More actions · Answer 1

Please post query, table definitions, index definitions and execution plan, as per http://www.sqlservercentral.com/articles/SQLServerCentral/66909/

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

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

johnitech.itech Hall of Fame Points: 3252 More actions · Answer 2

ok check below links

http://www.databasejournal.com/features/mssql/article.php/3618061/MS-SQL-Joins---Part-1.htm

http://scottonwriting.net/sowblog/archive/2010/07/13/howto-update-records-in-a-database-table-with-data-from-another-table-ms-sql-server.aspx

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 3

johnitech.itech (2/6/2012)

ok check below links

http://www.databasejournal.com/features/mssql/article.php/3618061/MS-SQL-Joins---Part-1.htm

http://scottonwriting.net/sowblog/archive/2010/07/13/howto-update-records-in-a-database-table-with-data-from-another-table-ms-sql-server.aspx%5B/quote%5D

What exactly do those have to do with a key lookup?

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

We walk in the dark places no others will enter
We stand on the bridge and no one may pass