sodonnel commented on a change in pull request #1028: HDFS-14617 - Improve
fsimage load time by writing sub-sections to the fsimage index
URL: https://github.com/apache/hadoop/pull/1028#discussion_r314259665
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File path:
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSImageFormatPBINode.java
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@@ -197,16 +203,66 @@ public static void updateBlocksMap(INodeFile file,
BlockManager bm) {
private final FSDirectory dir;
private final FSNamesystem fsn;
private final FSImageFormatProtobuf.Loader parent;
+ private ReentrantLock cacheNameMapLock;
+ private ReentrantLock blockMapLock;
Loader(FSNamesystem fsn, final FSImageFormatProtobuf.Loader parent) {
this.fsn = fsn;
this.dir = fsn.dir;
this.parent = parent;
+ cacheNameMapLock = new ReentrantLock(true);
+ blockMapLock = new ReentrantLock(true);
+ }
+
+ void loadINodeDirectorySectionInParallel(ExecutorService service,
+ ArrayList<FileSummary.Section> sections, String compressionCodec)
+ throws IOException {
+ LOG.info("Loading the INodeDirectory section in parallel with {} sub-" +
+ "sections", sections.size());
+ CountDownLatch latch = new CountDownLatch(sections.size());
+ final CopyOnWriteArrayList<IOException> exceptions =
+ new CopyOnWriteArrayList<>();
+ for (FileSummary.Section s : sections) {
+ service.submit(new Runnable() {
+ public void run() {
+ InputStream ins = null;
+ try {
+ ins = parent.getInputStreamForSection(s,
+ compressionCodec);
+ loadINodeDirectorySection(ins);
+ } catch (Exception e) {
+ LOG.error("An exception occurred loading INodeDirectories in " +
+ "parallel", e);
+ exceptions.add(new IOException(e));
+ } finally {
+ latch.countDown();
+ try {
+ ins.close();
+ } catch (IOException ioe) {
+ LOG.warn("Failed to close the input stream, ignoring", ioe);
+ }
+ }
+ }
+ });
+ }
+ try {
+ latch.await();
+ } catch (InterruptedException e) {
+ LOG.error("Interrupted waiting for countdown latch", e);
+ throw new IOException(e);
+ }
+ if (exceptions.size() != 0) {
+ LOG.error("{} exceptions occurred loading INodeDirectories",
+ exceptions.size());
+ throw exceptions.get(0);
+ }
+ LOG.info("Completed loading all INodeDirectory sub-sections");
}
void loadINodeDirectorySection(InputStream in) throws IOException {
final List<INodeReference> refList = parent.getLoaderContext()
.getRefList();
+ ArrayList<INode> inodeList = new ArrayList<>();
Review comment:
I missed this comment earlier. I have changed the 1000 to a constant.
For the cache in used, I have no concerns. Its a filename cache where all
the file names are loaded to it at startup time, so the same string can be
re-used if there are multiple files with the same name. It is not an LRU cache
or anything like that, but is a hashmap of filenames used to reduce the overall
heap used in the namenode. Loading it in batch like this will not affect the
usefulness of it.
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