Limiting counts and dates for SPC data

When designing a dashboard for SPC data, you can specify either a date period or a count for the data being retrieved. However, there is a way to limit retrievals by both a date period and a count:

Limiting counts

In some situations, you may want to apply a maximum record count to retrievals that are based on a date period.

For example, you may have a dashboard that is based on the last 90 days of data for a part that is typically produced for only a few weeks at a time. However, production for this part has increased and you now have thousands of data records for this part over the last 90 days, which makes your dashboard very slow to open. To improve the performance of this dashboard, you may decide to limit the retrieval to the last 500 records, while still ensuring that data older than 90 days is not included.

By default, SPC dashboard retrievals based on a date period are limited to the most recent 32,000 data records. You can limit these retrievals to a maximum of n records by adding dash_count=n to the Convert.db file. The number you specify for n must be greater than zero.

Limiting dates

In some situations, you may want for retrievals based on the "Last n records" to reflect only recent data.

For example, you may have a dashboard that is based on the last 500 data records for one standard. However, production for that part was suspended for several months, and you have only recently started producing this part again. So you are only interested in data from the last 30 days (up to 500 records).

By default, the date period of "All dates" is applied to SPC dashboard retrievals that are based on the "Last n records". You can limit these retrievals to a different date period by adding dash_period=p to the Convert.db file. The number you specify for p must be one of the following: