10.4.4 Incorporate DB triggers to update the CACHEIVL table
As mentioned earlier, the online shop was altered to enable invalidation of pages based on database updates. This was achieved by using database triggers to populate the CACHEIVL table whenever updates were performed. This enabled only the relevant cache fragments to be invalidated.
For example, if the details for an "acme" widget are updated in the database, the database trigger will put entries in the CACHEIVL table to remove:
| All cache page entries with specific information on the updated "acme" widget. |
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| All cache page entries that deal only with "acme" widgets and have multiple "acme" widgets on the one page. |
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| All cache page entries that deal with any brand of widget and may have a number of widgets from different manufacturers. |