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Explain What Is Wal And Hlog In Hbase? |
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Answer» WAL (Write Ahead Log) is similar to MySQL BIN log; it records all the changes occur in data. It is a standard sequence FILE by Hadoop and it stores HLogkey’s. These keys consist of a SEQUENTIAL number as well as actual data and are used to replay not yet persisted data after a server crash. So, in CASH of server failure WAL work as a life-line and retrieves the lost data’s. WAL (Write Ahead Log) is similar to MySQL BIN log; it records all the changes occur in data. It is a standard sequence file by Hadoop and it stores HLogkey’s. These keys consist of a sequential number as well as actual data and are used to replay not yet persisted data after a server crash. So, in cash of server failure WAL work as a life-line and retrieves the lost data’s. |
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