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https://issues.apache.org/jira/browse/HDDS-1461?focusedWorklogId=240312&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-240312
]
ASF GitHub Bot logged work on HDDS-1461:
----------------------------------------
Author: ASF GitHub Bot
Created on: 10/May/19 16:22
Start Date: 10/May/19 16:22
Worklog Time Spent: 10m
Work Description: lokeshj1703 commented on pull request #782: HDDS-1461.
Optimize listStatus api in OzoneFileSystem
URL: https://github.com/apache/hadoop/pull/782#discussion_r282951671
##########
File path:
hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/KeyManagerImpl.java
##########
@@ -1546,6 +1552,101 @@ public OmKeyInfo lookupFile(OmKeyArgs args) throws
IOException {
ResultCodes.NOT_A_FILE);
}
+ /**
+ * List the status for a file or a directory and its contents.
+ *
+ * @param args Key args
+ * @param recursive For a directory if true all the descendants of a
+ * particular directory are listed
+ * @param startKey Key from which listing needs to start. If startKey
exists
+ * its status is included in the final list.
+ * @param numEntries Number of entries to list from the start key
+ * @return list of file status
+ */
+ public List<OzoneFileStatus> listStatus(OmKeyArgs args, boolean recursive,
+ String startKey, long numEntries) throws IOException {
+ Preconditions.checkNotNull(args, "Key args can not be null");
+ String volumeName = args.getVolumeName();
+ String bucketName = args.getBucketName();
+ String keyName = args.getKeyName();
+
+ List<OzoneFileStatus> fileStatusList = new ArrayList<>();
+ try {
+ metadataManager.getLock().acquireBucketLock(volumeName, bucketName);
+ if (Strings.isNullOrEmpty(startKey)) {
+ OzoneFileStatus fileStatus = getFileStatus(args);
+ if (fileStatus.isFile()) {
+ return Collections.singletonList(fileStatus);
+ }
+ startKey = OzoneFSUtils.addTrailingSlashIfNeeded(keyName);
+ }
+
+ String seekKeyInDb =
+ metadataManager.getOzoneKey(volumeName, bucketName, startKey);
+ String keyInDb = OzoneFSUtils.addTrailingSlashIfNeeded(
+ metadataManager.getOzoneKey(volumeName, bucketName, keyName));
+ TableIterator<String, ? extends Table.KeyValue<String, OmKeyInfo>>
+ iterator = metadataManager.getKeyTable().iterator();
+ iterator.seek(seekKeyInDb);
+
+ if (!iterator.hasNext()) {
+ return Collections.emptyList();
+ }
+
+ if (iterator.key().equals(keyInDb)) {
+ // skip the key which needs to be listed
+ iterator.next();
+ }
+
+ while (iterator.hasNext() && numEntries - fileStatusList.size() > 0) {
+ String entryInDb = iterator.key();
+ OmKeyInfo value = iterator.value().getValue();
+ if (entryInDb.startsWith(keyInDb)) {
+ String entryKeyName = value.getKeyName();
+ if (recursive) {
+ // for recursive list all the entries
+ fileStatusList.add(new OzoneFileStatus(value, scmBlockSize,
+ !OzoneFSUtils.isFile(entryKeyName)));
+ iterator.next();
+ } else {
+ // get the child of the directory to list from the entry. For
+ // example if directory to list is /a and entry is /a/b/c where
+ // c is a file. The immediate child is b which is a directory. c
+ // should not be listed as child of a.
+ String immediateChild = OzoneFSUtils
+ .getImmediateChild(entryKeyName, keyName);
+ boolean isFile = OzoneFSUtils.isFile(immediateChild);
+ if (isFile) {
+ fileStatusList
+ .add(new OzoneFileStatus(value, scmBlockSize, !isFile));
+ iterator.next();
+ } else {
+ // if entry is a directory
+ fileStatusList.add(new OzoneFileStatus(immediateChild));
+ // skip the other descendants of this child directory.
+ iterator.seek(
+ getNextGreaterString(volumeName, bucketName,
immediateChild));
+ }
+ }
+ } else {
+ break;
+ }
+ }
+ } finally {
+ metadataManager.getLock().releaseBucketLock(volumeName, bucketName);
+ }
+ return fileStatusList;
+ }
+
+ private String getNextGreaterString(String volumeName, String bucketName,
+ String keyPrefix) {
+ // TODO: Use string codec
+ // Increment the last character of the string and return the new ozone key.
+ String nextPrefix = keyPrefix.substring(0, keyPrefix.length() - 1) +
+ String.valueOf((char) (keyPrefix.charAt(keyPrefix.length() - 1) + 1));
Review comment:
The first character in the ASCII table would not work in our case.
The second commit uses codec of RDBStore for handling the UTF-8 case.
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Issue Time Tracking
-------------------
Worklog Id: (was: 240312)
Time Spent: 40m (was: 0.5h)
> Optimize listStatus api in OzoneFileSystem
> ------------------------------------------
>
> Key: HDDS-1461
> URL: https://issues.apache.org/jira/browse/HDDS-1461
> Project: Hadoop Distributed Data Store
> Issue Type: Sub-task
> Components: Ozone Filesystem, Ozone Manager
> Reporter: Lokesh Jain
> Assignee: Lokesh Jain
> Priority: Major
> Labels: pull-request-available
> Time Spent: 40m
> Remaining Estimate: 0h
>
> Currently in listStatus we make multiple getFileStatus calls. This can be
> optimized by converting to a single rpc call for listStatus.
> Also currently listStatus has to traverse a directory recursively in order to
> list its immediate children. This happens because in OzoneManager all the
> metadata is stored in rocksdb sorted on keynames. The Jira also aims to fix
> this by using seek api provided by rocksdb.
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