com.hazelcast.spi.hotrestart.impl.gc

Class Snapshotter

java.lang.Object

com.hazelcast.spi.hotrestart.impl.gc.Snapshotter

public class Snapshotter
extends Object

Takes a snapshot of the Hot Restart Store state and saves it to the file named "chunk-snapshot.bin" in the Hot Restart Store's home directory. The file has a header followed by records describing each existing chunk file. Records are arbitrarily ordered. JDK's standard DataOutputStream is used to write the file.

This is the structure of the header:

1. snapshot's timestamp from System.nanoTime() — a long
2. number of records in the snapshot — an int.

This is the structure of a record describing a chunk file:

1. seq — a long
2. size / 256 — a char
3. garbage / 256 — a char
4. flags bitfield — a byte:
   • bit 0: whether it's a source chunk of the current GC cycle
   • bit 1: whether it's a survivor chunk of the current GC cycle
   • bit 2: whether it's a tombstone chunk

Field Summary

Fields

Modifier and Type	Field and Description
static String	CHUNK_SNAPSHOT_FNAME
static com.hazelcast.spi.properties.HazelcastProperty	GCSTATS_ENABLED
static String	PROPERTY_GCSTATS_ENABLED
static int	SOURCE_CHUNK_FLAG_MASK
static int	SURVIVOR_FLAG_MASK
static int	TOMBSTONE_FLAG_MASK

Method Summary

Methods inherited from class java.lang.Object

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

Field Detail

PROPERTY_GCSTATS_ENABLED

public static final String PROPERTY_GCSTATS_ENABLED

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Constant Field Values

GCSTATS_ENABLED

public static final com.hazelcast.spi.properties.HazelcastProperty GCSTATS_ENABLED

CHUNK_SNAPSHOT_FNAME

public static final String CHUNK_SNAPSHOT_FNAME

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Constant Field Values

SOURCE_CHUNK_FLAG_MASK

public static final int SOURCE_CHUNK_FLAG_MASK

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Constant Field Values

SURVIVOR_FLAG_MASK

public static final int SURVIVOR_FLAG_MASK

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Constant Field Values

TOMBSTONE_FLAG_MASK

public static final int TOMBSTONE_FLAG_MASK

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Constant Field Values