ScanInfo
class BTreeScanInfo extends java.lang.Object implements ScanInfo
Modifier and Type | Field | Description |
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private int |
stat_numColumnsFetched |
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private int |
stat_numdeleted_rows_visited |
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private int |
stat_numpages_visited |
Performance counters ...
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private int |
stat_numrows_qualified |
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private int |
stat_numrows_visited |
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private int |
stat_treeHeight |
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private FormatableBitSet |
stat_validColumns |
Constructor | Description |
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BTreeScanInfo(BTreeScan scan) |
Modifier and Type | Method | Description |
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java.util.Properties |
getAllScanInfo(java.util.Properties prop) |
Return all information gathered about the scan.
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private int stat_numpages_visited
private int stat_numrows_visited
private int stat_numrows_qualified
private int stat_numdeleted_rows_visited
private int stat_numColumnsFetched
private int stat_treeHeight
private FormatableBitSet stat_validColumns
BTreeScanInfo(BTreeScan scan)
public java.util.Properties getAllScanInfo(java.util.Properties prop) throws StandardException
This routine returns a list of properties which contains all information gathered about the scan. If a Property is passed in, then that property list is appeneded to, otherwise a new property object is created and returned.
Not all scans may support all properties, if the property is not supported then it will not be returned. The following is a list of properties that may be returned: numPagesVisited - the number of pages visited during the scan. For btree scans this number only includes the leaf pages visited. numRowsVisited - the number of rows visited during the scan. This number includes all rows, including: those marked deleted, those that don't meet qualification, ... numRowsQualified - the number of undeleted rows, which met the qualification. treeHeight (btree's only) - for btree's the height of the tree. A tree with one page has a height of 1. Total number of pages visited in a btree scan is (treeHeight - 1 + numPagesVisited). numColumnsFetched - the number of columns Fetched - partial scans will result in fetching less columns than the total number in the scan. columnsFetched - The FormatableBitSet.toString() method called on the validColumns arg. to the scan, unless validColumns was set to null, and in that case we will return "all". NOTE - this list will be expanded as more information about the scan is gathered and returned.
getAllScanInfo
in interface ScanInfo
prop
- Property list to fill in.StandardException
- Standard exception policy.Apache Derby V10.14 Internals - Copyright © 2004,2018 The Apache Software Foundation. All Rights Reserved.