1. The Complete Guide to Temporary Tables and Table Variables
Guy Glantser

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No use of the materials, in any form, is allowed,
unless receiving a prior written permission from Madeira Ltd

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

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

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

8. The Big Question:
When to Use What?

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

11. 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

12. 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

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

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

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

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17. Keep in Touch… Name: Guy Glantser Email Address: guy@madeiradata.com
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