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Special:Properties improve performance #1235

mwjames opened this Issue Oct 28, 2015 · 0 comments


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mwjames commented Oct 28, 2015

I never bothered (until now) to look on how Special:Properties (== PropertyUsageListLookup) composes the SELECT for the property list.

Now, that I need an API module that can serve a property list, the current SELECT is one of its worst kind since its performance degrades with increased ID_TABLE size (!== O(n)). Using the PROPERTY_STATISTICS_TABLE instead should give a close O(n) as only ID's are queried that we know is a property.


  • Left shows a select on the ID_TABLE for the SMW_NS_PROPERTY condition
  • Right shows an INNER JOIN on the ID_TABLE with ID's retrieved from the PROPERTY_STATISTICS_TABLE

@mwjames mwjames added this to the SMW 2.4 milestone Oct 28, 2015

mwjames added a commit that referenced this issue Oct 29, 2015

Merge pull request #1237 from SemanticMediaWiki/perf
Improve query performance in PropertyUsageListLookup, refs #1235

@mwjames mwjames closed this Oct 29, 2015

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