Package org.apache.iceberg.io

Class ContentCache

java.lang.Object
org.apache.iceberg.io.ContentCache
public class ContentCache extends Object
Class that provides file-content caching during reading.

The file-content caching is initiated by calling tryCache(InputFile). Given a FileIO, a file location string, and file length that is within allowed limit, ContentCache will return a ContentCache.CachingInputFile that is backed by the cache. Calling InputFile.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 Details

    • 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 Details

    • expireAfterAccess

      public long expireAfterAccess()

    • maxContentLength

      public long maxContentLength()

    • maxTotalBytes

      public long maxTotalBytes()

    • stats

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

    • get

      @Deprecated public org.apache.iceberg.io.ContentCache.CacheEntry get(String key, Function<String,org.apache.iceberg.io.ContentCache.FileContent> mappingFunction)
      Deprecated.
      will be removed in 1.7; use tryCache(InputFile) instead

    • getIfPresent

      @Deprecated public org.apache.iceberg.io.ContentCache.CacheEntry getIfPresent(String location)
      Deprecated.
      will be removed in 1.7; use tryCache(InputFile) instead

    • tryCache

      @Deprecated public InputFile tryCache(FileIO io, String location, long length)
      Deprecated.
      will be removed in 1.7; use tryCache(InputFile) instead

    • tryCache

      public InputFile tryCache(InputFile input)
      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 ContentCache.CachingInputFile that serve file reads backed by ContentCache.

      Parameters:
      input - an InputFile to cache
      Returns:
      a ContentCache.CachingInputFile if length is within allowed limit. Otherwise, a regular InputFile for given location.

    • invalidate

      public void invalidate(String key)

    • invalidateAll

      public void invalidateAll()

    • cleanUp

      public void cleanUp()

    • estimatedCacheSize

      public long estimatedCacheSize()

    • toString

      public String toString()
      Overrides:
      toString in class Object