org.apache.flink.table.runtime.functions.table.lookup

Class LookupCacheManager

java.lang.Object

org.apache.flink.table.runtime.functions.table.lookup.LookupCacheManager

@Internal
public class LookupCacheManager
extends Object

Managing shared caches across different subtasks.

In order to reduce the memory usage of cache, different subtasks of the same lookup join runner will share the same cache instance. Caches are managed by the identifier of the lookup table for which it is serving.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	LookupCacheManager.RefCountedCache A wrapper class of LookupCache which also tracks the reference count of it.

Method Summary

Modifier and Type	Method and Description
void	checkAllReleased()
void	clear()
static LookupCacheManager	getInstance() Get the shared instance of LookupCacheManager.
Map<String,LookupCacheManager.RefCountedCache>	getManagedCaches()
static void	keepCacheOnRelease(boolean toKeep)
LookupCache	registerCacheIfAbsent(String cacheIdentifier, LookupCache cache) Register a cache instance with identifier to the manager.
void	unregisterCache(String cacheIdentifier) Release the cache with the given identifier from the manager.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

getInstance

public static LookupCacheManager getInstance()

Get the shared instance of LookupCacheManager.

registerCacheIfAbsent

public LookupCache registerCacheIfAbsent(String cacheIdentifier,
                                         LookupCache cache)

Register a cache instance with identifier to the manager.

If the cache with the given identifier is already registered in the manager, this method will return the registered one, otherwise this method will register the given cache into the manager then return.

Parameters:

cacheIdentifier - identifier of the cache

cache - instance of cache trying to register

Returns:

instance of the shared cache

unregisterCache

public void unregisterCache(String cacheIdentifier)

Release the cache with the given identifier from the manager.

The manager will track a reference count of managed caches, and will close the cache if the reference count reaches 0.

keepCacheOnRelease

public static void keepCacheOnRelease(boolean toKeep)

checkAllReleased

public void checkAllReleased()

clear

public void clear()

getManagedCaches

public Map<String,LookupCacheManager.RefCountedCache> getManagedCaches()