Help:Special page "SemanticMediaWiki" - operational statistics - query cache statistics

Query cache statistics
Allows to view the collected query cache statistics
Collection
Loading... Screenshot showing the "Operational statistics" subpage of special page "SemanticMediaWiki" displaying the query cache statistics. (en) Screenshot showing the "Supplementary functions" section on special page "SemanticMediaWiki" holding the link to the "Operational statistics" page. (en)
Keywords
statistics · operational statistics · query cache statistics
Table of Contents

This page describes the query cache statistics as they can be seen on the "Operational statistics" page which is accessible when browsing on special page "SemanticMediaWiki". On that page it is found using the "Operational statistics" link in its "Supplementary functions" section and allows to tview collected statistics about the operation of the query result cache.

By default all users who are administrators (user group "sysop") or Semantic MediaWiki administrators (user group "smwadministrator") may see these statistics. This can be prevented by removing the user right "smw-admin" from the wiki administrators (user group "sysop") and additionally the respective user should not be assigned to be a Semantic MediaWiki administrator (user group "smwadministrator").

Example output

{
    "misses": {
        "nonEmbedded": {
            "API": 3,
            "SCI": {
                "CitationResourceMatchFinder": 22
            },
            "SSC": {
                "LibraryFactory": 2
            },
            "Undefined": 7,
            "SpecialAsk": 1
        },
        "embedded": {
            "AskParserFunction": 167,
            "UniquenessConstraintValueValidator": 11
        }
    },
    "hits": {
        "embedded": {
            "AskParserFunction": 1045,
            "UniquenessConstraintValueValidator": 1
        },
        "nonEmbedded": {
            "SCI": {
                "CitationResourceMatchFinder": 6
            },
            "SSC": {
                "LibraryFactory": 1
            }
        },
        "tempCache": {
            "embedded": 72
        }
    },
    "deletes": {
        "onNewRevisionFromEditComplete": 11,
        "onPropertyTableIdReferenceDisposal": 55,
        "onParserCachePurgeJob": 110,
        "onArticlePurge": 9
    },
    "noCache": {
        "byLimit": {
            "AskParserFunction": 143
        }
    },
    "medianRetrievalResponseTime": {
        "cached": 0.00065222722958465,
        "uncached": 0.0024844551177932
    },
    "ratio": {
        "hit": 0.8408,
        "miss": 0.1592
    },
    "meta": {
        "version": "1",
        "cacheLifetime": {
            "embedded": 604800,
            "nonEmbedded": 600
        },
        "collectionDate": {
            "start": "2017-03-11 08:11:10",
            "update": "2017-03-12 18:21:24"
        }
    }
}

Legend

• "misses" − the total attempts to retrieve data from the cache with unattainable responses, forcing a direct repository (relational database, triple-store etc.) retrieval
• "hits" − the total amount of cache retrievals from either
  • "embedded" − queries called from within a wiki page, or
  • "non-embedded" − requested by pages like Special:Ask or the API sources
• "deletes" − the total amount of cache eviction operations (either through a purge or query dependency)
• "noCache" − total indicates the amount of no attempt requests (limit=0 queries, 'no-cache' option etc.) to retrieve results from cache
• "medianRetrievalResponseTime" − the value of the median response time (in sec.) for cached and non-cached retrieval requests over the time span of the collection process
• "ratio" − the ration between misses and hits to cached data
• "meta" − general information on the cache:
  • "cacheLifetime" − query cache related configuration
  • "collectionDate" − start and last update of the query cache statistics

  Note: "misses" and "hits" are further split up to the subjects relating with the query cache, e.g. "API" for the Ask-API, "SpecialAsk" for special page "Ask", "SCI" for the Semanctic Cite extension or "SSC" for the Semantic Scribunto extension, etc.

See also

• Help page on the query result cache
• Help page on operational statistics