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https://issues.apache.org/jira/browse/HBASE-29667?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
huginn updated HBASE-29667:
---------------------------
Description:
When a data block is first written into the BucketCahce, BucketCache allocates
a bucket for it, generates and returns the corresponding BucketEntry, which
will later be placed into the BackingMap. I notice that BucketEntry sets the
Block Priority to MULTI during initialization. Is this a bug that causes the
BucketCache to only contain blocks with priorities MULTI and MEM, thereby
confusing single-access and multiple-access blocks? In fact, the BucketCache
has logic to upgrade SINGLE to MULTI when the block is accessed again, as well
as different cleanup logic for blocks with different block priorities.
{code:java}
public BucketEntry writeToCache(final IOEngine ioEngine, final BucketAllocator
alloc,
final LongAdder realCacheSize, Function<BucketEntry, Recycler>
createRecycler,
ByteBuffer metaBuff, final Long acceptableSize) throws IOException {
int len = data.getSerializedLength();
if (len == 0) {
return null;
}
if (isCachePersistent && data instanceof HFileBlock) {
len += Long.BYTES;
}
long offset = alloc.allocateBlock(len);
if (isPrefetch() && alloc.getUsedSize() > acceptableSize) {
alloc.freeBlock(offset, len);
return null;
}
boolean succ = false;
BucketEntry bucketEntry = null;
try {
int diskSizeWithHeader = (data instanceof HFileBlock)
? ((HFileBlock) data).getOnDiskSizeWithHeader()
: data.getSerializedLength();
bucketEntry = new BucketEntry(offset, len, diskSizeWithHeader,
accessCounter, inMemory,
createRecycler, getByteBuffAllocator());
bucketEntry.setDeserializerReference(data.getDeserializer());
...
}
BucketEntry(long offset, int length, int onDiskSizeWithHeader, long
accessCounter,
long cachedTime, boolean inMemory, Function<BucketEntry, Recycler>
createRecycler,
ByteBuffAllocator allocator) {
if (createRecycler == null) {
throw new IllegalArgumentException("createRecycler could not be null!");
}
setOffset(offset);
this.length = length;
this.onDiskSizeWithHeader = onDiskSizeWithHeader;
this.accessCounter = accessCounter;
this.cachedTime = cachedTime;
this.priority = inMemory ? BlockPriority.MEMORY : BlockPriority.MULTI;
this.refCnt = RefCnt.create(createRecycler.apply(this));
this.markedAsEvicted = new AtomicBoolean(false);
this.allocator = allocator;
}
{code}
was: !screenshot-1.png!
> The block priority is initialized as MULTI when the data block is first
> written into the BucketCache
> ----------------------------------------------------------------------------------------------------
>
> Key: HBASE-29667
> URL: https://issues.apache.org/jira/browse/HBASE-29667
> Project: HBase
> Issue Type: Bug
> Components: BucketCache
> Reporter: huginn
> Assignee: huginn
> Priority: Major
> Attachments: screenshot-1.png
>
>
> When a data block is first written into the BucketCahce, BucketCache
> allocates a bucket for it, generates and returns the corresponding
> BucketEntry, which will later be placed into the BackingMap. I notice that
> BucketEntry sets the Block Priority to MULTI during initialization. Is this a
> bug that causes the BucketCache to only contain blocks with priorities MULTI
> and MEM, thereby confusing single-access and multiple-access blocks? In fact,
> the BucketCache has logic to upgrade SINGLE to MULTI when the block is
> accessed again, as well as different cleanup logic for blocks with different
> block priorities.
> {code:java}
> public BucketEntry writeToCache(final IOEngine ioEngine, final
> BucketAllocator alloc,
> final LongAdder realCacheSize, Function<BucketEntry, Recycler>
> createRecycler,
> ByteBuffer metaBuff, final Long acceptableSize) throws IOException {
> int len = data.getSerializedLength();
> if (len == 0) {
> return null;
> }
> if (isCachePersistent && data instanceof HFileBlock) {
> len += Long.BYTES;
> }
> long offset = alloc.allocateBlock(len);
> if (isPrefetch() && alloc.getUsedSize() > acceptableSize) {
> alloc.freeBlock(offset, len);
> return null;
> }
> boolean succ = false;
> BucketEntry bucketEntry = null;
> try {
> int diskSizeWithHeader = (data instanceof HFileBlock)
> ? ((HFileBlock) data).getOnDiskSizeWithHeader()
> : data.getSerializedLength();
> bucketEntry = new BucketEntry(offset, len, diskSizeWithHeader,
> accessCounter, inMemory,
> createRecycler, getByteBuffAllocator());
> bucketEntry.setDeserializerReference(data.getDeserializer());
> ...
> }
> BucketEntry(long offset, int length, int onDiskSizeWithHeader, long
> accessCounter,
> long cachedTime, boolean inMemory, Function<BucketEntry, Recycler>
> createRecycler,
> ByteBuffAllocator allocator) {
> if (createRecycler == null) {
> throw new IllegalArgumentException("createRecycler could not be null!");
> }
> setOffset(offset);
> this.length = length;
> this.onDiskSizeWithHeader = onDiskSizeWithHeader;
> this.accessCounter = accessCounter;
> this.cachedTime = cachedTime;
> this.priority = inMemory ? BlockPriority.MEMORY : BlockPriority.MULTI;
> this.refCnt = RefCnt.create(createRecycler.apply(this));
> this.markedAsEvicted = new AtomicBoolean(false);
> this.allocator = allocator;
> }
> {code}
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