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https://issues.apache.org/jira/browse/FLINK-987?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14054702#comment-14054702
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Stephan Ewen commented on FLINK-987:
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I see the point. Actually, that was the reasoning why my first suggestion of
the interfaces always explicitly had the current memory segment and offset in
the parameters. This would help optimize the critical and common case where a
record fits into one memory segment.
Why don't you make a prototype implementation following suggestion (2), then we
microbenchmark it and polish it?
> Extend TypeSerializers and -Comparators to work directly on Memory Segments
> ---------------------------------------------------------------------------
>
> Key: FLINK-987
> URL: https://issues.apache.org/jira/browse/FLINK-987
> Project: Flink
> Issue Type: Improvement
> Components: Local Runtime
> Affects Versions: 0.6-incubating
> Reporter: Stephan Ewen
> Assignee: Aljoscha Krettek
> Fix For: 0.6-incubating
>
>
> As per discussion with [~till.rohrmann], [~uce], [~aljoscha], we suggest to
> change the way that the TypeSerialzers/Comparators and
> DataInputViews/DataOutputViews work.
> The goal is to allow more flexibility in the construction on the binary
> representation of data types, and to allow partial deserialization of
> individual fields. Both is currently prohibited by the fact that the
> abstraction of the memory (into which the data goes) is a stream abstraction
> ({{DataInputView}}, {{DataOutputView}}).
> An idea is to offer a random-access buffer like view for construction and
> random-access deserialization, as well as various methods to copy elements in
> a binary fashion between such buffers and streams.
> A possible set of methods for the {{TypeSerializer}} could be:
> {code}
> long serialize(T record, TargetBuffer buffer);
>
> T deserialize(T reuse, SourceBuffer source);
>
> void ensureBufferSufficientlyFilled(SourceBuffer source);
>
> <X> X deserializeField(X reuse, int logicalPos, SourceBuffer buffer);
>
> int getOffsetForField(int logicalPos, int offset, SourceBuffer buffer);
>
> void copy(DataInputView in, TargetBuffer buffer);
>
> void copy(SourceBuffer buffer,, DataOutputView out);
>
> void copy(DataInputView source, DataOutputView target);
> {code}
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