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https://issues.apache.org/jira/browse/CASSANDRA-20190?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17937122#comment-17937122
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Dmitry Konstantinov commented on CASSANDRA-20190:
-------------------------------------------------
Bloom filter:
* write and store flow
** org.apache.cassandra.utils.obs.OffHeapBitSet#set(long) - uses
Memory.setByte(..), so it is order agnostic
** org.apache.cassandra.utils.obs.OffHeapBitSet#serialize - writes to output
stream memory as a sequence of buffers, by copying the buffers as is
* load and read flow
** org.apache.cassandra.utils.BloomFilterSerializer#deserialize - uses
FBUtilities.copy(in, new MemoryOutputStream(memory), byteCount) to load memory
as is from the input stream
** org.apache.cassandra.utils.obs.IBitSet#get uses
org.apache.cassandra.io.util.Memory#getByte, so it is order agnostic
So, it is agnostic to the memory order in Memory and it will not be affected by
using LE in Memory#get/putXByByte
> MemoryUtil.setInt/getInt and similar use the wrong endianness
> -------------------------------------------------------------
>
> Key: CASSANDRA-20190
> URL: https://issues.apache.org/jira/browse/CASSANDRA-20190
> Project: Apache Cassandra
> Issue Type: Bug
> Components: Local/Other
> Reporter: Branimir Lambov
> Assignee: Dmitry Konstantinov
> Priority: Normal
> Time Spent: 1h
> Remaining Estimate: 0h
>
> `NativeCell`, `NativeClustering` and `NativeDecoratedKey` use the above
> methods from `MemoryUtil` to write and read data from native memory. As far
> as I can see they are meant to write data in big endian. They do not (they
> always correct to little endian).
> Moreover, they disagree with their `ByByte` versions on big-endian machines
> (which is only likely an issue on aligned-access architectures (x86 and arm
> should be fine)).
> The same is true for the methods in `Memory`, used by compression metadata as
> well as index summaries.
> We need to verify that this does not cause any problems, and to change the
> methods to behave as expected and document the behaviour by explicitly using
> `ByteOrder.LITTLE_ENDIAN` for any data that may have been persisted on disk
> with the wrong endianness.
>
> The current MemoryUtil behaviour (before the fix):
> ||Native
> order||MemoryUtil.setX||MemoryUtil.setXByByte||MemoryUtil.getX||MemoryUtil.getXByByte||
> |BE|LE|BE|LE|BE|
> |LE|LE|LE|LE|LE|
> shortly: MemoryUtil.setX/getX is LE, MemoryUtil.setXByByte/getXByByte is
> Native
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