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HBASE-28805: Chunked persistence of backing map for persistent bucket cache. - #6183
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Apache-HBase
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Aug 29, 2024
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| byte[] convertToBytes (long value) { | ||
| byte[] bytes = new byte[Long.BYTES]; | ||
| int length = bytes.length; | ||
| for (int i = 0; i < length; i++) { | ||
| bytes[length - i - 1] = (byte) (value & 0xFF); | ||
| value >>= 8; | ||
| } | ||
| return bytes; | ||
| } | ||
| long convertToLong(byte[] bytes) { | ||
| long value = 0; | ||
| for (byte b : bytes) { | ||
| value = (value << 8) + (b & 0xFF); | ||
| } | ||
| return value; | ||
| } | ||
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There are already Bytes.toBytes, Bytes.toLong for this.
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| int blockCount = 0; | ||
| int chunkCount = 0; | ||
| BucketCacheProtos.BackingMap.Builder builder = BucketCacheProtos.BackingMap.newBuilder(); |
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Why are we creating proto builder here? Can't this go to BucketProtoUtils?
Apache-HBase
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… cache. The persistent bucket cache implementation feature relies on the persistence of backing map to a persistent file. the protobuf APIs are used to serialise the backing map and its related structures into the file. An asynchronous thread periodically flushes the contents of backing map to the persistence file. The protobuf library has a limitation of 2GB on the size of protobuf messages. If the size of backing map increases beyond 2GB, an unexpected exception is reported in the asynchronous thread and stops the persister thread. This causes the persistent file go out of sync with the actual bucket cache. Due to this, the bucket cache shrinks to a smaller size after a cache restart. Checksum errors are also reported. This Jira tracks the implementation of introducing chunking of the backing map to persistence such that every protobuf is smaller than 2GB in size. Change-Id: I8623ad2eaf1d1a56f96bc3120b14e5229ae55c42
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Is it possible to move all the serialization/deserialization logic to BucketProtoUtils?
| } | ||
| private static BucketCacheProtos.BackingMap toPB(Map<BlockCacheKey, BucketEntry> backingMap) { | ||
| static void toPB(BucketCache cache, FileOutputStream fos, long chunkSize) throws IOException{ |
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nit: We should rename it to serializeAsPB.
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| fos.write(PB_MAGIC_V2); | ||
| long numChunks = backingMap.size() / persistenceChunkSize; | ||
| if (backingMap.size() % persistenceChunkSize != 0) { | ||
| numChunks += 1; | ||
| } | ||
| LOG.debug("persistToFile: before persisting backing map size: {}, " | ||
| + "fullycachedFiles size: {}, chunkSize: {}, numberofChunks: {}", | ||
| backingMap.size(), fullyCachedFiles.size(), persistenceChunkSize, numChunks); | ||
| fos.write(Bytes.toBytes(persistenceChunkSize)); | ||
| fos.write(Bytes.toBytes(numChunks)); |
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Since we are already passing the output stream to BucketProtoUtils, who's now also responsible for serialization, can we just move everything there?
Apache-HBase
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Change-Id: I3eaddcef94a711e63eeefd47063f074d0a57c984
Apache-HBase
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Apache-HBase
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Apache-HBase
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Change-Id: I082a83ef841125eed00d3ccd660bd2beb95dc4f9
Apache-HBase
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Sep 3, 2024
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jhungund added a commit
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Sep 4, 2024
… cache. (apache#6183) HBASE-28805: Chunked persistence of backing map for persistent bucket cache. Signed-off-by: Wellington Chevreuil <wchevreuil@apache.org> Change-Id: I72efe71040a8970f87a8b2a08c4c4ac1ceef74bc
jhungund added a commit
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Sep 4, 2024
… cache. (apache#6183) HBASE-28805: Chunked persistence of backing map for persistent bucket cache. Signed-off-by: Wellington Chevreuil <wchevreuil@apache.org> Change-Id: I72efe71040a8970f87a8b2a08c4c4ac1ceef74bc
jhungund added a commit
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Sep 6, 2024
… cache. (apache#6183) HBASE-28805: Chunked persistence of backing map for persistent bucket cache. Signed-off-by: Wellington Chevreuil <wchevreuil@apache.org> Change-Id: I72efe71040a8970f87a8b2a08c4c4ac1ceef74bc
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The persistent bucket cache implementation feature relies on the persistence of backing map to a persistent file. the protobuf APIs are used to serialise the backing map and its related structures into the file.
An asynchronous thread periodically flushes the contents of backing map to the persistence file.
The protobuf library has a limitation of 2GB on the size of protobuf messages. If the size of backing map increases beyond 2GB, an unexpected exception is reported in the asynchronous thread and stops the persister thread. This causes the persistent file go out of sync with the actual bucket cache. Due to this, the bucket cache shrinks to a smaller size after a cache restart. Checksum errors are also reported.
This Jira tracks the implementation of introducing chunking of the backing map to persistence such that every protobuf is smaller than 2GB in size.
Change-Id: I8623ad2eaf1d1a56f96bc3120b14e5229ae55c42