From semantic-mediawiki.org

Configuration parameter details:
Name $smwgExperimentalFeatures
Description Sets experimental features
Default setting See below
Software Semantic MediaWiki
Since version
Until version still available
Configuration Query performance · Store settings · Miscellaneous
Keyword query features · query performance · store setup · store · mysql · postgresql

$smwgExperimentalFeatures is a configuration parameter to set experimental features 1 that are considered stable. However they can be disabled in case any unforeseen behaviour is being observed. The configuration parameter was introduced in Semantic MediaWiki 3.0.0Released on 11 October 2018 and compatible with MW 1.27.0 - 1.31.x.. The default setting for this configuration parameter was changed with the introduction of a new option in Semantic MediaWiki 3.1.0Released on 23 September 2019 and compatible with MW 1.31.0 - 1.33.x..23

Default setting[edit]


This means that the prefetch query feature42 for resolving query requests is being used. Moreover the parser function #show will directly access the database to request an output for one particular entity.

Available options[edit]

The options enabled by default are highlighted bold.
  • SMW_QUERYRESULT_PREFETCH – Sets that the prefetch query feature4 for resolving query requests is being used. This option is specific to relational data stores, i.e. MySQL and PostgreSQL.2
  • SMW_SHOWPARSER_USE_CURTAILMENT – Sets the parser function #show to use a short cut and circumventing the QueryEngine by directly accessing the database since it will always only request an output for one particular entity.3

Changing the default setting[edit]

To modify the setting to this configuration parameter, add one of the following lines to your "LocalSettings.php" file after the enableSemantics() call:

Disabling all experimental query features

To disable all experimental features just set 0 instead of the constants as shown in the above section on available options:

$smwgExperimentalFeatures = 0;
This setting allows to retain the behavior prior to the introduction of the new experimental feature in case issues arise.

Note: "gh:smw:2461" was removed with "gh:smw:3277" prior to the release of SMW 3.0.0.


  1. ^  Semantic MediaWiki: GitHub pull request gh:smw:2936
  2. a b c  Semantic MediaWiki: GitHub pull request gh:smw:4063
  3. a b  Semantic MediaWiki: GitHub pull request gh:smw:4078
  4. a b  Semantic MediaWiki: GitHub issue gh:smw:3722