public
interface
WriteAheadLog
| com.netflix.astyanax.WriteAheadLog |
 Known Indirect Subclasses
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Class Overview
Base interface for a write ahead log. The purpose of the WAL is to provide atomicity and durability when writing to Cassandra. Before writing to cassandra a record is written to the WAL which is assumed to stable storage able to survive from a crash or hardware failure. After a crash the system will inspect the WAL for records and replay them. If a record is successfully written to cassandra it will be removed from the WAL.
Summary
| Public Methods | |||||||||||
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Add an entry to WAL before it is sent to Cassandra.
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Read the next entry to retry from the wall.
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Remove an entry from the WAL after it was successfully written to
cassandra
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Retry an entry retrieved by calling getNextEntry();
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Public Methods
public abstract WriteAheadEntry createEntry ()
Add an entry to WAL before it is sent to Cassandra.
Throws
| WalException |
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public abstract WriteAheadEntry readNextEntry ()
Read the next entry to retry from the wall. Call remove if successful or retryEntry if unable to write to cassandra.
public abstract void removeEntry (WriteAheadEntry entry)
Remove an entry from the WAL after it was successfully written to cassandra
public abstract void retryEntry (WriteAheadEntry entry)
Retry an entry retrieved by calling getNextEntry();