[HBASE-27940] Midkey metadata in root index block would always be ignored by BlockIndexReader.readMultiLevelIndexRoot

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.0-alpha-4, 2.4.17, 2.5.5, 4.0.0-alpha-1
• Fix Version/s: 2.6.0, 2.4.18, 2.5.6, 3.0.0-beta-1
• Component/s: HFile
• Assignee: chenglei
• Reporter: chenglei
• Created: 17/Jun/23 03:10
• Updated: 18/Jun/23 20:15
• Resolved: 17/Jun/23 13:38

Description

After HBASE-27053， checksum is removed from the HFileBlock ByteBuff in FSReaderImpl.readBlockDataInternal once the checksum is verified, so HFileBlock.buf does not include checksum, but for BlockIndexReader.readMultiLevelIndexRoot, after read root index entries , it still subtracts the checksum to check if the midkey metadat exists, the midkey metadata would always be ignored:

public void readMultiLevelIndexRoot(HFileBlock blk, final int numEntries) throws IOException {
      DataInputStream in = readRootIndex(blk, numEntries);
      // after reading the root index the checksum bytes have to
      // be subtracted to know if the mid key exists.
      int checkSumBytes = blk.totalChecksumBytes();
      if ((in.available() - checkSumBytes) < MID_KEY_METADATA_SIZE) {
        // No mid-key metadata available.
        return;
      }
      midLeafBlockOffset = in.readLong();
      midLeafBlockOnDiskSize = in.readInt();
      midKeyEntry = in.readInt();
 }

Issue Links

• is related to: HBASE-27053 IOException during caching of uncompressed block to the block cache.
• links to: GitHub Pull Request #5296
• links to: GitHub Pull Request #5297
• links to: GitHub Pull Request #5298