The Complete Guide to Temporary Tables and Table Variables Guy Glantser

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First, a Basic Comparison… Temporary Table Table Variable Storage tempdb Scope Session Batch Constraints Yes

First, a Basic Comparison… Temporary Table Table Variable Indexes Yes Statistics Yes No Recompilations Yes No

First, a Basic Comparison… Temporary Table Table Variable T-Log Footprint Full Minimal Table Parameters No Yes Parallelism Yes No

The Big Question: When to Use What?

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Bottom Line If the batch is executed only once in a while Use a temporary table with OPTION (RECOMPILE)

Bottom Line If not (the batch is executed many times per second) If the number of rows in the table is relatively fixed Use a temporary table

Bottom Line If the number of rows in the table varies all the time If performance with a temporary table is acceptable (due to recompiles) Use a temporary table

Bottom Line If performance with a temporary table is not acceptable If performance with a table variable is acceptable Use a table variable

Bottom Line If performance is not acceptable either way Try a hybrid solution

Bottom Line When using a table-valued parameter Consider using trace flag 2453

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Keep in Touch… Name: Guy Glantser Email Address: guy@madeiradata.com Twitter: @guy_glantser Blog: www.linkedin.com/in/glantser Podcast: www.sqlserverradio.com Image courtesy of Mister GC / FreeDigitalPhotos.net