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https://issues.apache.org/jira/browse/HDFS-17463?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17837681#comment-17837681
]
ASF GitHub Bot commented on HDFS-17463:
---------------------------------------
XbaoWu commented on code in PR #6736:
URL: https://github.com/apache/hadoop/pull/6736#discussion_r1567203473
##########
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSImageFormatPBINode.java:
##########
@@ -628,25 +638,59 @@ private void loadRootINode(INodeSection.INode p) {
public final static class Saver {
private long numImageErrors;
- private static long buildPermissionStatus(INodeAttributes n) {
- return n.getPermissionLong();
+ private static long buildPermissionStatus(INodeAttributes n,
+ boolean enableSaveSplitIdStringTable) {
+ if(enableSaveSplitIdStringTable){
+ return n.getPermissionLong();
+ } else {
+ StringTable serialStringTable =
SerialNumberManager.getSerialStringTable();
+ Map<String, Integer> stringMap = StreamSupport
+ .stream(serialStringTable.spliterator(), false)
+ .collect(Collectors.toMap(Map.Entry::getValue, Map.Entry::getKey));
+
+ long permission = n.getPermissionLong();
+ permission = USER.BITS.combine(stringMap.get(n.getUserName()),
permission);
+ permission = GROUP.BITS.combine(stringMap.get(n.getGroupName()),
permission);
+ return permission;
+ }
}
- private static AclFeatureProto.Builder buildAclEntries(AclFeature f) {
+ private static AclFeatureProto.Builder buildAclEntries(AclFeature f,
+ boolean enableSaveSplitIdStringTable) {
AclFeatureProto.Builder b = AclFeatureProto.newBuilder();
+ Map<String, Integer> stringMap = null;
+ if(!enableSaveSplitIdStringTable){
+ StringTable serialStringTable =
SerialNumberManager.getSerialStringTable();
+ stringMap = StreamSupport.stream(serialStringTable.spliterator(),
false)
+ .collect(Collectors.toMap(Map.Entry::getValue,
Map.Entry::getKey));
+ }
+
for (int pos = 0, e; pos < f.getEntriesSize(); pos++) {
e = f.getEntryAt(pos);
+ if(!enableSaveSplitIdStringTable){
+ e = (int)
NAME.BITS.combine(stringMap.get(AclEntryStatusFormat.getName(e)), e);
+ }
b.addEntries(e);
}
return b;
}
- private static XAttrFeatureProto.Builder buildXAttrs(XAttrFeature f) {
+ private static XAttrFeatureProto.Builder buildXAttrs(XAttrFeature f,
boolean enableSaveSplitIdStringTable) {
XAttrFeatureProto.Builder b = XAttrFeatureProto.newBuilder();
+ Map<String, Integer> stringMap = null;
+ if(!enableSaveSplitIdStringTable){
+ StringTable serialStringTable =
SerialNumberManager.getSerialStringTable();
Review Comment:
Yes, when enableSaveSplitIdStringTable is false, getSerialStringTable is
called ; conversely, getStringTable is called. The mapping relations stored in
these two StringTable are different.
> Support the switch StringTable Split ID feature
> -----------------------------------------------
>
> Key: HDFS-17463
> URL: https://issues.apache.org/jira/browse/HDFS-17463
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: namenode
> Affects Versions: 3.2.0, 3.3.5, 3.3.3, 3.3.4
> Reporter: wangzhihui
> Priority: Major
> Labels: pull-request-available
> Attachments: Image_struct.png, error.png
>
>
> desc:
> *
> Hadoop 3.2 introduced optimization features for HDFS StringTable
> (b60ca37914b22550e3630fa02742d40697decb3), It resulted in lower versions of
> Hadoop upgraded to 3.2 and later versions not supporting downgrade
> operations.
> !error.png!
> * This issue has also been discussed in HDFS-14831, and it is recommended to
> revert the feature, but it cannot fundamentally solve the problem。
> *
> Therefore, we have added an optimization to support downgrading
>
> Solution:
> * First, we will add the "dfs. image. save. splitId. stringTable" conf
> switch "StringTable optimization feature" is enabled
> * When the conf value is false, an Image file compatible with lower versions
> of HDFS is generated to support downgrading.
> *
> The difference in HDFS Image file format between Hadoop 3.1.1 and Hadoop 3.2
> is shown in the following figure.
> * With the sub-sections feature introduced in HDFS-14617, Protobuf can
> support compatible reading.
> *
> The data structure causing incompatible differences is mainly StringTable.
> !Image_struct.png|width=396,height=163!
> * In "dfs.image.save.splitId.stringTable = false " the Id generation order
> of StringTable starts from 0 to Integer.Max. When true, the Id value range
> follows the latest rules.
>
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