Slow to render a chart with 40K points

[ricky_ru]

 Dears,

Table Structure/

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MAC_SPEED
MAC_REV

ITEMDATETIME

MACHINE_NAME

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Please refer to the images attached. There are 4 fields for the table which describe the machine's status(speed, rev). The data is actually populated from the collector into the database every n seconds.

The keyword in the table is itemdatetime.  There is a prompt to let user select the machine name. For a particular machine, there are 40K data. The SQL is simple like this for the chart:

SELECT SUM(MAC_SPEED),SUM(MAC_REV) FROM $tHE_TABLE WHERE machine_name='#3' GROUP BY ITEMDATATIME.



1) The chart rendering is slow. For 40 K data, it needs more than 1 min in cognos 10.2.2. ( I think we have narrowed down the scope , the most time consuming part is to render the chart with 40k points).

Is there any way to make it fast. Because there are several similar charts in the dashboard and it will be much slow to render them all.

2) The business is we need to find the particular exceptional points which deviate the pattern. Is there any better solution for this comparing to the chart mentioned?


Thanks,
Ricky