org.apache.iceberg.io

Class ContentCache

java.lang.Object

org.apache.iceberg.io.ContentCache

public class ContentCache
extends java.lang.Object

Class that provides file-content caching during reading.

The file-content caching is initiated by calling tryCache(FileIO, String, long). Given a FileIO, a file location string, and file length that is within allowed limit, ContentCache will return a CachingInputFile that is backed by the cache. Calling CachingInputFile#newStream() will return a ByteBufferInputStream backed by list of ByteBuffer from the cache if such file-content exist in the cache. If the file-content does not exist in the cache yet, a regular InputFile will be instantiated, read-ahead, and loaded into the cache before returning ByteBufferInputStream. The regular InputFile is also used as a fallback if cache loading fail.

Constructor Summary

Constructors

Constructor and Description
ContentCache(long expireAfterAccessMs, long maxTotalBytes, long maxContentLength) Constructor for ContentCache class.

Method Summary

Modifier and Type	Method and Description
void	cleanUp()
long	estimatedCacheSize()
long	expireAfterAccess()
org.apache.iceberg.io.ContentCache.CacheEntry	get(java.lang.String key, java.util.function.Function<java.lang.String,org.apache.iceberg.io.ContentCache.CacheEntry> mappingFunction)
org.apache.iceberg.io.ContentCache.CacheEntry	getIfPresent(java.lang.String location)
void	invalidate(java.lang.String key)
void	invalidateAll()
long	maxContentLength()
long	maxTotalBytes()
com.github.benmanes.caffeine.cache.stats.CacheStats	stats()
java.lang.String	toString()
InputFile	tryCache(FileIO io, java.lang.String location, long length) Try cache the file-content of file in the given location upon stream reading.

Methods inherited from class java.lang.Object

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

Constructor Detail

ContentCache

public ContentCache(long expireAfterAccessMs,
                    long maxTotalBytes,
                    long maxContentLength)

Constructor for ContentCache class.

Parameters:

expireAfterAccessMs - controls the duration for which entries in the ContentCache are hold since last access. Must be greater or equal than 0. Setting 0 means cache entries expire only if it gets evicted due to memory pressure.

maxTotalBytes - controls the maximum total amount of bytes to cache in ContentCache. Must be greater than 0.

maxContentLength - controls the maximum length of file to be considered for caching. Must be greater than 0.

Method Detail

expireAfterAccess

public long expireAfterAccess()

maxContentLength

public long maxContentLength()

maxTotalBytes

public long maxTotalBytes()

stats

public com.github.benmanes.caffeine.cache.stats.CacheStats stats()

get

public org.apache.iceberg.io.ContentCache.CacheEntry get(java.lang.String key,
                                                         java.util.function.Function<java.lang.String,org.apache.iceberg.io.ContentCache.CacheEntry> mappingFunction)

getIfPresent

public org.apache.iceberg.io.ContentCache.CacheEntry getIfPresent(java.lang.String location)

tryCache

public InputFile tryCache(FileIO io,
                          java.lang.String location,
                          long length)

Try cache the file-content of file in the given location upon stream reading.

If length is longer than maximum length allowed by ContentCache, a regular InputFile and no caching will be done for that file. Otherwise, this method will return a CachingInputFile that serve file reads backed by ContentCache.

Parameters:

io - a FileIO associated with the location.

location - URL/path of a file accessible by io.

length - the known length of such file.

Returns:

a CachingInputFile if length is within allowed limit. Otherwise, a regular InputFile for given location.

invalidate

public void invalidate(java.lang.String key)

invalidateAll

public void invalidateAll()

cleanUp

public void cleanUp()

estimatedCacheSize

public long estimatedCacheSize()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object