Mystery of memory fraction in Showplan XML

If you examine Showplan XML, you may find an entry like  <MemoryFractions Input=”1″ Output=”1″ /> on some operators .  They are internal parameters used by query memory grant to save overall memory usage, and “fraction” means how much this operator is allowed to use from “total additional memory” (please see previous post for definition on additional memory)….

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Understanding SQL server memory grant

This article describes how query memory grant works in Microsoft SQL Server. It applies to both SQL2005 and SQL2008. Written by Jay Choe, Microsoft SQL Server Engine. ——————————————————————————– Query memory grant (a.k.a. query work buffer) is a part of server memory used to store temporary row data while sorting and joining rows. It is called…

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