Re: performance versus order of fields in row

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От
Jan Wieck
Тема
Re: performance versus order of fields in row
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3FC4249C.8050406@Yahoo.com
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performance versus order of fields in row "D. Stimits" <stimits@comcast.net>
Re: performance versus order of fields in row Tom Lane <tgl@sss.pgh.pa.us>
Re: performance versus order of fields in row Jan Wieck <JanWieck@Yahoo.com>
Re: performance versus order of fields in row Tom Lane <tgl@sss.pgh.pa.us>
Tom Lane wrote:

>"D. Stimits"  writes:
>  
>
>>I'm not looking for an exact answer here, but instead something more 
>>"rule of thumb". If I have a table with many fields, and I retrieving 
>>small groups of fields during a SELECT, whereby the groups of fields are 
>>indexed and/or clustered, will I get a faster select in the left-most 
>>fields, or the right-most fields? Or will it not matter?
>>    
>>
>
>Fields earlier in the table definition (further to the left) are
>marginally faster to access than ones further to the right.  I doubt it
>would be real noticeable unless you had hundreds of fields altogether.
>

Do we still "cache" field offsets for not-nullable-fixed-size columns?


Jan

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