Hello!

        Got a DB with traffic statictics stored. And a SELECT statement which 
shows traffic volume per days also divided by regions - local traffic and 
global.
       Thus SELECT statement returns about some (in about 10-20) rows paired 
like this:

ttype (text)| volume (int)| tdate (date)
----------------------------------------
local       | xxxxx       | some-date
global      | xxxxx       | some-date

        When executing this SELECT (see SELECT.A above) it executes in about 
700 ms, but when I want wipe out all info about local traffic, with query like 
this:
      SELECT * FROM ( SELECT.A ) a WHERE type = 'global';
It executes about 10000 ms - more then 10 TIMES SLOWER!

 Why this could be?



-------------------------------------------------
Initial Query - SELECT.A (executes about 700 ms)

SELECT 
      CASE is_local(aa.uaix) WHEN true THEN 'local' 
                             ELSE 'global' END AS TType, 
      aa.cDate AS TDate,
      SUM(aa.data) AS Value 
FROM (
      SELECT 
            a.uaix AS uaix, 
            cDate AS cDate, 
            SUM(a.data) AS data 
      FROM (
             (
             SELECT toIP AS uaix, 
                    cDate AS cDate, 
                    SUM(packetSize) AS data
              FROM vw_stats
             WHERE interface <> 'inet'
                  AND cdate = '01.09.2005'
                  AND fromIP << '192.168.0.0/16'
                  AND NOT (toIP << '192.168.0.0/16')
             GROUP BY 1,2
            )
           UNION 
           (
            SELECT fromIP AS uaix, 
                   cDate AS cDate, 
                   SUM(packetSize) AS data
             FROM vw_stats
             WHERE interface <> 'inet'
                   AND cdate = '01.09.2005'
                   AND toIP << '192.168.0.0/16'
                   AND NOT (fromIP << '192.168.0.0/16')
             GROUP BY 1,2
            )
      ) a
      GROUP BY 1,2
) aa
GROUP BY 1,2
ORDER BY 1,2

-----------------------------------------------------------
Query with local info filtered (executes about 10000 ms)

SELECT * FROM (
<HERE PLACED SELECT.A>
) aaa WHERE aaa.TType = 'global';


-----------------------------------------------------------

Running Postgresql 8.0.3 on FreeBSD 5.3

  

-- 
Best regards,
 eVl                          mailto:[EMAIL PROTECTED]



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