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Message Posted: Mon, 12 Mar 2001 @ 15:25:03 GMT


     
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Subj:   Secondary Indexes
 
From:   Howard Bradley

Dear all ,

Could anyone tell me if there is a limit to the number of secondary indexes (sp!) one should have on a table .

We have a 90 million row transactional table with 3 different DATE columns , each of which is defined individually as a VALUE ORDERED secondary index (the table covers 3 years worth of data) .

We have now added 3 new columns which relate to week numbers for particular measures and I am considering adding 3 further VALUE ORDERED secondary indexes making it 6 in total .

Unfortunately , a week does not relate to 7 distinct days on the table hence the need to add the week number (a business week runs from mid Saturday to mid Saturday and we cannot get TIME data without a fundamental re write of the operational system so in order to identify which business week a particular transaction relates to we need to load the week number) . I realise there will be an overhead on space and at load time but is there any impact to query times or anything else I should consider before implementing the 3 new indexes .


Thanks in advance .

Howard .



     
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