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https://issues.apache.org/jira/browse/CASSANDRA-20190?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17911199#comment-17911199
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Dmitry Konstantinov edited comment on CASSANDRA-20190 at 1/8/25 6:36 PM:
-------------------------------------------------------------------------
||Entity||Used Memory methods||Serialize/deserialize logic||Notes||
|BloomFilter (OffHeapBitSet)
assuming new format|setByte
getByte|OffHeapBitSet#serialize
{code:java}
DataOutputPlus.write(bytes, 0, bytes.size()); -> list of native order byte
buffers -> copy them as is{code}OffHeapBitSet#deserialize
{code:java}
FBUtilities.copy(in, new MemoryOutputStream(memory), byteCount), read using
byte[] chunks {code}|Order agnostic|
|IndexSummary.offsets|getInt|IndexSummaryBuilder
{code:java}
offsets = new SafeMemoryWriter(4 *
maxExpectedEntries).order(ByteOrder.LITTLE_ENDIAN);
// it was native before CASSANDRA-17723
...
offsets.writeInt((int) entries.length()); {code}
IndexSummary.IndexSummarySerializer#serialize
{code:java}
int offset = t.offsets.getInt(i * 4) + baseOffset;
// our serialization format for this file uses native byte order, so if this is
different to the
// default Java serialization order (BIG_ENDIAN) we have to reverse our bytes
offset = Integer.reverseBytes(offset);
out.writeInt(offset); {code}IndexSummary.IndexSummarySerializer#deserialize
{code:java}
FBUtilities.copy(in, new MemoryOutputStream(offsets), offsets.size()); {code}
copy file content as is to memory| * file format: LE (for offsets)
* memory format: LE|
was (Author: dnk):
||Entity||Used Memory methods||Serialize/deserialize logic||Notes||
|BloomFilter (OffHeapBitSet)
assuming new format|setByte
getByte|OffHeapBitSet#serialize
{code:java}
DataOutputPlus.write(bytes, 0, bytes.size()); -> list of native order byte
buffers -> copy them as is{code}OffHeapBitSet#deserialize
{code:java}
FBUtilities.copy(in, new MemoryOutputStream(memory), byteCount), read using
byte[] chunks {code}|Order agnostic|
> 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
> Priority: Normal
>
> `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:
> ||Native
> order||MemoryUtil.setX||MemoryUtil.setXByByte||MemoryUtil.getX||MemoryUtil.getXByByte||
> |BE|LE|BE|LE|BE|
> |LE|LE|LE|LE|LE|
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