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https://issues.apache.org/jira/browse/GEODE-6579?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16812888#comment-16812888
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Darrel Schneider commented on GEODE-6579:
-----------------------------------------
I added a thread local byte array cache and ran a jmh benchmark to see how it
compared to just creating a new byte array each time.
The thread local cache was ~20% faster in this micro-benchmark. The following
show the readString calls/ms for different length strings. The benchmark
preserialized the data so the only thing measured in it was the actual
deserialization of the string.
||length||old||new||diff||
|35|18237|22278|+18%|
|70|13778|17062|+20%|
|140|8759|10931|+20%|
|280|4466|5962|+25%|
|560|2101|2712|+23%|
|1120|1144|1411|+18%|
> Creating a String during deserialization could be optimized
> -----------------------------------------------------------
>
> Key: GEODE-6579
> URL: https://issues.apache.org/jira/browse/GEODE-6579
> Project: Geode
> Issue Type: Improvement
> Components: serialization
> Reporter: Darrel Schneider
> Assignee: Darrel Schneider
> Priority: Major
> Labels: optimization
> Time Spent: 50m
> Remaining Estimate: 0h
>
> When creating a string during deserialization from data that we know is in
> the ASCII character set (each character can be represented by one byte) we
> currently read all the bytes into a temporary byte array and then create a
> String instance by giving it that byte array. The String constructor has to
> create its own char array and then copy all the bytes into it. After that the
> byte array is garbage.
> We could instead directly create a char array, fill it by reading each byte
> from the DataInput into it and then using reflection to directly set this
> char array as the value field of the String instance we just created (as an
> empty String). This prevents an extra copy of the data and reduces garbage
> creation.
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