6.2.6 Results caching
Publish or Perish uses a local cache for the data returned by queries. If you re-run a query, then Publish or Perish will retrieve the results data from the local cache instead of contacting Google Scholar again, provided that the cached data is still "fresh". If the cached data is too old, or if no cached data exists, then Publish or Perish sends the query to Google Scholar and stores the new results in the local cache for subsequent use.
The Query Date and Cache Date columns in the list view show the status of the query and cached data.
- Query Date is the date on which you last performed the query, i.e., last issued the Lookup [Direct] command.
- Cache Date is the date on which the data were last retrieved from Google Scholar.
Typically, the Query Date is the same or more recent than the Cache Date. If the Query Date is more recent, this means that the query on that date used the cached results rather than contacting Google Scholar. This is normal behavior.
Out-of-date cached data
If the Cache Date is too long ago or missing altogether, then the list view will display a small red arrow in front of the query. This means that the Cache Date is exceeds the maximum cache age specified in the Preferences - Queries dialog box.
In the case of out-of-date cached data, Publish or Perish will resubmit the query to Google Scholar the next time that you use the Lookup command. This happens automatically when you issue that command; you do not have to do anything special for that.
If you want to refresh the cache before the data expires, use the Lookup Direct command. This might occasionally turn up some extra results, but there is no point in using Lookup Direct more than once every few days; this merely increases the load on Google Scholar and increases the chance that your computer may be temporarily denied access by Google Scholar. Under normal circumstances you should rely on Publish or Perish's automatic caching implementation.