kaijchen commented on code in PR #3811:
URL: https://github.com/apache/ozone/pull/3811#discussion_r992076932
##########
hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/keyvalue/KeyValueContainerCheck.java:
##########
@@ -230,44 +232,100 @@ private void scanData(DataTransferThrottler throttler,
Canceler canceler)
onDiskContainerData.setDbFile(dbFile);
- ContainerLayoutVersion layout = onDiskContainerData.getLayoutVersion();
-
try (DBHandle db = BlockUtils.getDB(onDiskContainerData, checkConfig);
BlockIterator<BlockData> kvIter = db.getStore().getBlockIterator(
onDiskContainerData.getContainerID(),
onDiskContainerData.getUnprefixedKeyFilter())) {
while (kvIter.hasNext()) {
BlockData block = kvIter.nextBlock();
- for (ContainerProtos.ChunkInfo chunk : block.getChunks()) {
- File chunkFile = layout.getChunkFile(onDiskContainerData,
- block.getBlockID(), ChunkInfo.getFromProtoBuf(chunk));
-
- if (!chunkFile.exists()) {
- // concurrent mutation in Block DB? lookup the block again.
- String blockKey =
- onDiskContainerData.blockKey(block.getBlockID().getLocalID());
- BlockData bdata = db.getStore()
- .getBlockDataTable()
- .get(blockKey);
- // In EC, client may write empty putBlock in padding block nodes.
- // So, we need to make sure, chunk length > 0, before declaring
- // the missing chunk file.
- if (bdata != null && bdata.getChunks().size() > 0 && bdata
- .getChunks().get(0).getLen() > 0) {
- throw new IOException(
- "Missing chunk file " + chunkFile.getAbsolutePath());
+
+ // If holding read lock for the entire duration, including wait() calls
+ // in DataTransferThrottler, would effectively make other threads
+ // throttled.
+ // Here try optimistically and retry with the container lock to
+ // make sure reading the latest record. If the record is just removed,
+ // the block should be skipped to scan.
+ try {
+ scanBlock(db, block, throttler, canceler);
+ } catch (IOException ex) {
+ if (getBlockDataFromDBWithLock(db, block) == null) {
+ if (LOG.isDebugEnabled()) {
+ LOG.debug("Scanned outdated blockData {} in container {}.",
+ block, containerID);
}
- } else if (chunk.getChecksumData().getType()
- != ContainerProtos.ChecksumType.NONE) {
- verifyChecksum(block, chunk, chunkFile, layout, throttler,
- canceler);
+ } else {
+ throw new IOException(ex);
}
}
}
}
}
+ /**
+ * Attempt to read the block data without the container lock.
+ * The block onDisk might be in modification by other thread and not yet
+ * flushed to DB, so the content might be outdated.
+ *
+ * @param db DB of container
+ * @param block last queried blockData
+ * @return blockData in DB
+ * @throws IOException
+ */
+ private BlockData getBlockDataFromDB(DBHandle db, BlockData block)
+ throws IOException {
+ String blockKey =
+ onDiskContainerData.blockKey(block.getBlockID().getLocalID());
+ return db.getStore().getBlockDataTable().get(blockKey);
+ }
+
+ /**
+ * Attempt to read the block data with the container lock.
+ * The container lock ensure the latest DB record could be retrieved, since
+ * other block related write operation will acquire the container write
lock.
+ *
+ * @param db DB of container
+ * @param block last queried blockData
+ * @return blockData in DB
+ * @throws IOException
+ */
+ private BlockData getBlockDataFromDBWithLock(DBHandle db, BlockData block)
+ throws IOException {
+ container.readLock();
+ try {
+ return getBlockDataFromDB(db, block);
+ } finally {
+ container.readUnlock();
+ }
+ }
+
+ private void scanBlock(DBHandle db, BlockData block,
+ DataTransferThrottler throttler, Canceler canceler) throws IOException {
+ ContainerLayoutVersion layout = onDiskContainerData.getLayoutVersion();
+
+ for (ContainerProtos.ChunkInfo chunk : block.getChunks()) {
+ File chunkFile = layout.getChunkFile(onDiskContainerData,
+ block.getBlockID(), ChunkInfo.getFromProtoBuf(chunk));
+
+ if (!chunkFile.exists()) {
+ // concurrent mutation in Block DB? lookup the block again.
+ BlockData bdata = getBlockDataFromDB(db, block);
Review Comment:
It would be better to abstract a method which takes `BlockData` as input and
do the verification.
So we can make unit tests easier to write for this issue.
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