com.sleepycat.je.tree
Class VLSNCache
java.lang.Object
com.sleepycat.je.tree.VLSNCache
- Direct Known Subclasses:
- VLSNCache.DefaultCache
public abstract class VLSNCache
- extends Object
Caches the VLSN sequence for the LN entries in a BIN, when VLSN preservation
and caching are configured.
A VLSN is added to the cache when an LN is evicted from a BIN. When the LN
is resident, there is no need for caching because the LN contains the VLSN.
See BIN.setTarget. This strategy works because an LN is always cached
during a read or write operation, and only evicted after that based on
eviction policies.
Field Summary |
static VLSNCache |
EMPTY_CACHE
An EMPTY_CACHE is used initially for each BIN until the need arises to
add to the cache. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
EMPTY_CACHE
public static VLSNCache EMPTY_CACHE
- An EMPTY_CACHE is used initially for each BIN until the need arises to
add to the cache. The cache will remain empty if LNs are never evicted
or version caching is not configured, which is always the case for
standalone JE.
VLSNCache
public VLSNCache()
get
public abstract long get(int idx)
set
public abstract VLSNCache set(int idx,
long val,
IN parent)
copy
public abstract VLSNCache copy(int from,
int to,
int n)
getMemorySize
public abstract long getMemorySize()
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