Character vs. Numeric Searches

Lately quite a few users have asked me if a search on a uniquely indexed column is faster if it is numeric than character (these are all equality matches).

I have told them 'no', that their fastest search will be on that uniquely indexed column, regardless of data type (path #2 in the DBA Guide, 19-17). I have told them width of column matters more than data type. You'll have more physical io on a wide index because Oracle can't cache as much of the index. The smaller the index, the more that can be cached.

Am I right? or all wet? My answer is encountering much skepticism.

• jean

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| Jean Anderson, DBA                       email:  jean_at_seismo.css.gov  |

| SAIC Open Systems Division, MS A2-F         or:  jean_at_esosun.css.gov  |

| 10210 Campus Point Drive                 phone:  (619)458-2727        |


| San Diego, CA  92121                       fax:  (619)458-4993        |


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|                execute sp_disclaimer _at_opinion="mine"                  |


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