|Modifier and Type||Method and Description|
Estimate the worst-case cost to query with the given filter.
Get the query plan for the given filter.
Query the index.
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
public DiffIndex(DiffCollector collector)
The returned value is supposed to be an estimate and doesn't have to be very accurate. Please note this method is called on each index whenever a query is run, so the method should be reasonably fast (not read any data itself, or at least not read too much data).
If an index implementation can not query the data, it has to return
An implementation should only filter the result if it can do so easily and efficiently; the query engine will verify the data again (in memory) and check for access rights.
The method is only called if this index is used for the given query and
selector, which is only the case if the given index implementation
returned the lowest cost for the given filter. If the implementation
Double.MAX_VALUE in the getCost method for the given
filter, then this method is not called. If it is still called, then it is
supposed to throw an exception (as it would be an internal error of the
EXPLAIN SELECTquery, or for logging purposes. The result should be human readable.
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