natas_hw
/
cassandra
mirror of https://github.com/apache/cassandra
0
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Align buffer with commitlog segment size 

Patch by brandonwilliams and blambov; reviewed by bereng for
CASSANDRA-19471
This commit is contained in:
Brandon Williams 2024-03-20 11:21:05 -05:00
parent fdfc0019de
commit 389479c9a2
2 changed files with 13 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
CHANGES.txt
View File

@ -1,4 +1,5 @@
5.0-beta2
* Align buffer with commitlog segment size (CASSANDRA-19471)
* Ensure SAI indexes empty byte buffers for types that allow them as a valid input (CASSANDRA-19461)
* Deprecate Python 3.7 and earlier, but allow cqlsh to run with Python 3.6-3.11 (CASSANDRA-19467)
* Set uuid_sstable_identifiers_enabled to true in cassandra-latest.yaml (CASSANDRA-19460)

21
src/java/org/apache/cassandra/db/commitlog/DirectIOSegment.java
View File

@ -184,11 +184,16 @@ public class DirectIOSegment extends CommitLogSegment
@Override
public SimpleCachedBufferPool createBufferPool()
{
// The direct buffer must be aligned with the file system block size. We cannot enforce that during
// allocation, but we can get an aligned slice from the allocated buffer. The buffer must be oversized by the
// alignment unit to make it possible.
// Since the allocated buffer may be offset by up to fsBlockSize -
// 1 bytes, the buffer must be oversized by that amount. Alignment
// will make sure both the start and end of the buffer are aligned,
// cutting off any remaining bytes from both sides. Note that if we
// oversize by fsBlockSize bytes and the buffer happens to be
// already aligned, neither the start nor the end of the buffer
// will be adjusted and the resulting buffer will be bigger than
// expected.
return new SimpleCachedBufferPool(DatabaseDescriptor.getCommitLogMaxCompressionBuffersInPool(),
DatabaseDescriptor.getCommitLogSegmentSize() + fsBlockSize,
DatabaseDescriptor.getCommitLogSegmentSize() + fsBlockSize - 1,
BufferType.OFF_HEAP) {
@Override
public ByteBuffer createBuffer()
@ -202,12 +207,10 @@ public class DirectIOSegment extends CommitLogSegment
ByteBufferUtil.writeZeroes(original.duplicate(), original.limit());
ByteBuffer alignedBuffer;
if (original.alignmentOffset(0, fsBlockSize) > 0)
alignedBuffer = original.alignedSlice(fsBlockSize);
else
alignedBuffer = original.slice().limit(segmentSize);
alignedBuffer = original.alignedSlice(fsBlockSize);
assert alignedBuffer.limit() >= segmentSize : String.format("Bytebuffer slicing failed to get required buffer size (required=%d, current size=%d", segmentSize, alignedBuffer.limit());
assert alignedBuffer.limit() == segmentSize : String.format("Bytebuffer slicing failed to get required buffer size (required=%d, current size=%d", segmentSize, alignedBuffer.limit());
assert alignedBuffer.limit() == alignedBuffer.capacity() : String.format("Bytebuffer limit and capacity do not match (limit=%d, capacity=%d", alignedBuffer.limit(), alignedBuffer.capacity());
assert alignedBuffer.alignmentOffset(0, fsBlockSize) == 0 : String.format("Index 0 should be aligned to %d page size.", fsBlockSize);
assert alignedBuffer.alignmentOffset(alignedBuffer.limit(), fsBlockSize) == 0 : String.format("Limit should be aligned to %d page size", fsBlockSize);