On Thu, Sep 26, 2002 at 03:01:35PM +0530, Shridhar Daithankar wrote: Content-Description: Mail message body > The index creation query was > > CREATE INDEX index1 ON tablename (esn,min,datetime); > > What if I put datetime ahead? It's likely the the datetime field will have high > degree of locality being log data..
The order of fields depends on what you're using it for. For example, you can use the above index for a query using the conditions: esn = 'aaa' esn = 'bbb' and min = 'xxx' but not for queries with only datetime = '2002-09-26' min = 'ddd' and datetime = '2002-10-02' The fields can only be used left to right. This is where a single multicolumn index differs from multiple indexes of different columns. Have you used EXPLAIN ANALYSE to determine whether your indexes are being used optimally? -- Martijn van Oosterhout <[EMAIL PROTECTED]> http://svana.org/kleptog/ > There are 10 kinds of people in the world, those that can do binary > arithmetic and those that can't. ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
