public class DelegatingKeyValueScanner extends java.lang.Object implements KeyValueScanner
Modifier and Type | Field and Description |
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protected KeyValueScanner |
delegate |
Constructor and Description |
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DelegatingKeyValueScanner(KeyValueScanner delegate) |
Modifier and Type | Method and Description |
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boolean |
backwardSeek(Cell key)
Seek the scanner at or before the row of specified Cell, it firstly
tries to seek the scanner at or after the specified Cell, return if
peek KeyValue of scanner has the same row with specified Cell,
otherwise seek the scanner at the first Cell of the row which is the
previous row of specified KeyValue
|
void |
close()
Close the KeyValue scanner.
|
void |
enforceSeek()
Does the real seek operation in case it was skipped by
seekToRowCol(KeyValue, boolean) (TODO: Whats this?).
|
Cell |
getNextIndexedKey() |
long |
getSequenceID()
Get the sequence id associated with this KeyValueScanner.
|
boolean |
isFileScanner() |
Cell |
next()
Return the next Cell in this scanner, iterating the scanner
|
Cell |
peek()
Look at the next Cell in this scanner, but do not iterate scanner.
|
boolean |
realSeekDone()
We optimize our store scanners by checking the most recent store file
first, so we sometimes pretend we have done a seek but delay it until the
store scanner bubbles up to the top of the key-value heap.
|
boolean |
requestSeek(Cell kv,
boolean forward,
boolean useBloom)
Similar to
KeyValueScanner.seek(org.apache.hadoop.hbase.Cell) (or KeyValueScanner.reseek(org.apache.hadoop.hbase.Cell) if forward is true) but only
does a seek operation after checking that it is really necessary for the
row/column combination specified by the kv parameter. |
boolean |
reseek(Cell key)
Reseek the scanner at or after the specified KeyValue.
|
boolean |
seek(Cell key)
Seek the scanner at or after the specified KeyValue.
|
boolean |
seekToLastRow()
Seek the scanner at the first KeyValue of last row
|
boolean |
seekToPreviousRow(Cell key)
Seek the scanner at the first Cell of the row which is the previous row
of specified key
|
boolean |
shouldUseScanner(Scan scan,
java.util.SortedSet<byte[]> columns,
long oldestUnexpiredTS)
Allows to filter out scanners (both StoreFile and memstore) that we don't
want to use based on criteria such as Bloom filters and timestamp ranges.
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protected KeyValueScanner delegate
public DelegatingKeyValueScanner(KeyValueScanner delegate)
public Cell peek()
KeyValueScanner
peek
in interface KeyValueScanner
public Cell next() throws java.io.IOException
KeyValueScanner
next
in interface KeyValueScanner
java.io.IOException
public boolean seek(Cell key) throws java.io.IOException
KeyValueScanner
seek
in interface KeyValueScanner
key
- seek valuejava.io.IOException
public boolean reseek(Cell key) throws java.io.IOException
KeyValueScanner
reseek
in interface KeyValueScanner
key
- seek value (should be non-null)java.io.IOException
public void close()
KeyValueScanner
close
in interface KeyValueScanner
public boolean shouldUseScanner(Scan scan, java.util.SortedSet<byte[]> columns, long oldestUnexpiredTS)
KeyValueScanner
shouldUseScanner
in interface KeyValueScanner
scan
- the scan that we are selecting scanners forcolumns
- the set of columns in the current column family, or null if
not specified by the scanoldestUnexpiredTS
- the oldest timestamp we are interested in for
this query, based on TTLpublic boolean requestSeek(Cell kv, boolean forward, boolean useBloom) throws java.io.IOException
KeyValueScanner
KeyValueScanner.seek(org.apache.hadoop.hbase.Cell)
(or KeyValueScanner.reseek(org.apache.hadoop.hbase.Cell)
if forward is true) but only
does a seek operation after checking that it is really necessary for the
row/column combination specified by the kv parameter. This function was
added to avoid unnecessary disk seeks by checking row-column Bloom filters
before a seek on multi-column get/scan queries, and to optimize by looking
up more recent files first.requestSeek
in interface KeyValueScanner
forward
- do a forward-only "reseek" instead of a random-access seekuseBloom
- whether to enable multi-column Bloom filter optimizationjava.io.IOException
public long getSequenceID()
KeyValueScanner
getSequenceID
in interface KeyValueScanner
public boolean realSeekDone()
KeyValueScanner
realSeekDone
in interface KeyValueScanner
public void enforceSeek() throws java.io.IOException
KeyValueScanner
KeyValueScanner.realSeekDone()
first.enforceSeek
in interface KeyValueScanner
java.io.IOException
public boolean isFileScanner()
isFileScanner
in interface KeyValueScanner
public boolean backwardSeek(Cell key) throws java.io.IOException
KeyValueScanner
backwardSeek
in interface KeyValueScanner
key
- seek KeyValuejava.io.IOException
public boolean seekToPreviousRow(Cell key) throws java.io.IOException
KeyValueScanner
seekToPreviousRow
in interface KeyValueScanner
key
- seek valuejava.io.IOException
public boolean seekToLastRow() throws java.io.IOException
KeyValueScanner
seekToLastRow
in interface KeyValueScanner
java.io.IOException
public Cell getNextIndexedKey()
getNextIndexedKey
in interface KeyValueScanner