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Object org.apache.spark.util.SizeEstimator
public class SizeEstimator
:: DeveloperApi :: Estimates the sizes of Java objects (number of bytes of memory they occupy), for use in memory-aware caches.
Based on the following JavaWorld article: http://www.javaworld.com/javaworld/javaqa/2003-12/02-qa-1226-sizeof.html
Constructor Summary | |
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SizeEstimator()
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Method Summary | |
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static long |
estimate(Object obj)
Estimate the number of bytes that the given object takes up on the JVM heap. |
Methods inherited from class Object |
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equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Methods inherited from interface org.apache.spark.Logging |
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initializeIfNecessary, initializeLogging, isTraceEnabled, log_, log, logDebug, logDebug, logError, logError, logInfo, logInfo, logName, logTrace, logTrace, logWarning, logWarning |
Constructor Detail |
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public SizeEstimator()
Method Detail |
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public static long estimate(Object obj)
This is useful for determining the amount of heap space a broadcast variable will occupy on each executor or the amount of space each object will take when caching objects in deserialized form. This is not the same as the serialized size of the object, which will typically be much smaller.
obj
- (undocumented)
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