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https://issues.apache.org/jira/browse/KAFKA-8037?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17035541#comment-17035541
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Sophie Blee-Goldman commented on KAFKA-8037:
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Ha, yes good catch I'll fix the typo in 2)
That's a good point about later valid records potentially overwriting a
corrupted one; I suppose we can't just load the two changelogs one after
another, and would have to restore from both at the same time by choosing the
next record in the original order. Might be tricky to synchronize but not
impossible.
I think this should still work for key deserialization errors though; we would
still copy the plain key bytes with a null value on restore, which is treated
as a delete by the store (without ever having to deserialize the corrupted key)
> KTable restore may load bad data
> --------------------------------
>
> Key: KAFKA-8037
> URL: https://issues.apache.org/jira/browse/KAFKA-8037
> Project: Kafka
> Issue Type: Improvement
> Components: streams
> Reporter: Matthias J. Sax
> Priority: Minor
> Labels: pull-request-available
>
> If an input topic contains bad data, users can specify a
> `deserialization.exception.handler` to drop corrupted records on read.
> However, this mechanism may be by-passed on restore. Assume a
> `builder.table()` call reads and drops a corrupted record. If the table state
> is lost and restored from the changelog topic, the corrupted record may be
> copied into the store, because on restore plain bytes are copied.
> If the KTable is used in a join, an internal `store.get()` call to lookup the
> record would fail with a deserialization exception if the value part cannot
> be deserialized.
> GlobalKTables are affected, too (cf. KAFKA-7663 that may allow a fix for
> GlobalKTable case). It's unclear to me atm, how this issue could be addressed
> for KTables though.
> Note, that user state stores are not affected, because they always have a
> dedicated changelog topic (and don't reuse an input topic) and thus the
> corrupted record would not be written into the changelog.
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