Wikimedia Bugzilla is closed!

Created attachment 10695 [details]
Allow cache to be used for "remote autocomplete"

## What
For each "remote autocomplete" request, the database goes into full-search mode which causes various bottlenecks for the server and increases waiting time for users.

## Solution

Introduce a switch ($sfgCacheAutocompleteValues) which allows to use standard caching mechanism for results that use the same property_name / substring combination.

This can help to increase the response time for users using field definitions that uses "remote autocomplete" and decrease unnecessary database selects that are initiated by each single "remote autocomplete" request.

This solution is for users who want to use "remote autocomplete" to be able to fetch all possible results while at the same time don't have to sacrifice performance for ached results. 

## Implementation 

see patch 

The patch introduces two new globals
* $sfgCacheAutocompleteValues   = true/false;
* $sfgCacheAutocompleteTimeOut  = 60 * 60 * 6; (6h)
* $sfgFormCacheType is used to determine the cache type and is shared with SForm cache. 

## Invalidation of cache 

For a sophisticated update logic of added/obsolete property/values pairs one would have to use $wgHooks['SMWStore::updateDataBefore'] and $wgHooks['smwDeleteSemanticData'] to track and invalidate pairs but since that would take some more effort to implement sfgCacheAutocompleteTimeOut is used to ensure cache objects are invalidate after a set time out.