Query Cache Probes

Query Cache Probes
The query cache probes are fired when executing any query. The query-cache-hit query
is triggered when a query exists in the query cache and can be used to return the query cache
information. The arguments contain the original query text and the number of rows returned from the
query cache for the query. If the query is not within the query cache, or the query cache is not enabled,
then the query-cache-miss probe is triggered instead.
query-cache-hit(query, rows)
query-cache-miss(query)
• query-cache-hit: Triggered when the query has been found within the query cache. The first
argument, query, contains the original text of the query. The second argument, rows, is an integer
containing the number of rows in the cached query.
• query-cache-miss: Triggered when the query is not found within the query cache. The first
argument, query, contains the original text of the query.
The query cache probes are best combined with a probe on the main query so that you can determine
the differences in times between using or not using the query cache for specified queries. For example,
in the following D script, the query and query cache information are combined into the information
output during monitoring
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