背景说明
通过日志数据文件恢复消息
Kafka将生产者发送给它的消息数据内容保存至日志数据文件中，该文件以该段的基准偏移量左补齐0命名，文件后缀为“.log”。分区中的每条message由offset来表示它在这个分区中的偏移量，这个offset并不是该Message在分区中实际存储位置，而是逻辑上的一个值（Kafka中用8字节长度来记录这个偏移量），但它却唯一确定了分区中一条Message的逻辑位置，同一个分区下的消息偏移量按照顺序递增（这个可以类比下数据库的自增主键）。另外，从dump出来的日志数据文件的字符值中可以看到消息体的各个字段的内容值。
解决方案
命令查看
[root@ljhan2 kafka]# bin/kafka-run-class.sh kafka.tools.DumpLogSegments
Parse a log file and dump its contents to the console, useful for debugging a seemingly corrupt log segment.
Option Description
------ -----------
--deep-iteration if set, uses deep instead of shallow
iteration.
--files <String: file1, file2, ...> REQUIRED: The comma separated list of data
and index log files to be dumped.
--index-sanity-check if set, just checks the index sanity
without printing its content. This is
the same check that is executed on
broker startup to determine if an index
needs rebuilding or not.
--key-decoder-class [String] if set, used to deserialize the keys. This
class should implement kafka.serializer.
Decoder trait. Custom jar should be
available in kafka/libs directory.
(default: kafka.serializer.StringDecoder)
--max-message-size <Integer: size> Size of largest message. (default: 5242880)
--offsets-decoder if set, log data will be parsed as offset
data from the __consumer_offsets topic.
--print-data-log if set, printing the messages content when
dumping data logs. Automatically set if
any decoder option is specified.
--transaction-log-decoder if set, log data will be parsed as
transaction metadata from the
__transaction_state topic.
--value-decoder-class [String] if set, used to deserialize the messages.
This class should implement kafka.
serializer.Decoder trait. Custom jar
should be available in kafka/libs
directory. (default: kafka.serializer.
StringDecoder)
--verify-index-only if set, just verify the index log without
printing its content.
[root@ljhan2 kafka]#
命令执行
[root@ljhan2 kafka]# bin/kafka-run-class.sh kafka.tools.DumpLogSegments --files /work/uReplicator/cluster1/kafka_data/a-0/00000000000000000000.log --deep-iteration --print-data-log
Dumping /work/uReplicator/cluster1/kafka_data/a-0/00000000000000000000.log
Starting offset: 0
offset: 0 position: 0 CreateTime: 1610187094280 isvalid: true keysize: 2 valuesize: 2 magic: 2 compresscodec: NONE producerId: -1 producerEpoch: -1 sequence: -1 isTransactional: false headerKeys: [] key: a1 payload: a1
offset: 1 position: 72 CreateTime: 1610187109018 isvalid: true keysize: 2 valuesize: 2 magic: 2 compresscodec: NONE producerId: -1 producerEpoch: -1 sequence: -1 isTransactional: false headerKeys: [] key: a2 payload: a2
[root@ljhan2 kafka]# bin/kafka-run-class.sh kafka.tools.DumpLogSegments --files /work/uReplicator/cluster1/kafka_data/a-0/00000000000000000000.index --deep-iteration --print-data-log
Dumping /work/uReplicator/cluster1/kafka_data/a-0/00000000000000000000.index
offset: 0 position: 0
[root@ljhan2 kafka]#
[root@ljhan2 kafka]# bin/kafka-run-class.sh kafka.tools.DumpLogSegments --files /work/uReplicator/cluster1/kafka_data/a-0/00000000000000000000.timeindex --deep-iteration --print-data-log
Dumping /work/uReplicator/cluster1/kafka_data/a-0/00000000000000000000.timeindex
timestamp: 1610189276640 offset: 23
Found timestamp mismatch in :/work/uReplicator/cluster1/kafka_data/a-0/00000000000000000000.timeindex
Index timestamp: 0, log timestamp: 1610187094280
Found out of order timestamp in :/work/uReplicator/cluster1/kafka_data/a-0/00000000000000000000.timeindex
Index timestamp: 0, Previously indexed timestamp: 1610189276640
[root@ljhan2 kafka]#
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