swamirishi commented on code in PR #9079:
URL: https://github.com/apache/ozone/pull/9079#discussion_r2413442520
##########
hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/SnapshotDiffManager.java:
##########
@@ -1223,6 +1273,81 @@ Set<String> getDeltaFiles(OmSnapshot fromSnapshot,
toSnapshot.getSnapshotTableKey()));
}
+ /**
+ * Resolve the VersionMeta of the ancestor snapshot (fromSnapshotId)
+ * that the given snapshot (toSnapshot) was built on.
+ * Traverses the snapshot chain backwards using prevSnapId.
+ *
+ * @param toSnapshot the target snapshot.
+ * @param fromSnapshotId UUID of the source snapshot.
+ * @return the resolved VersionMeta of the source that was used to build the
target.
+ */
+ private OmSnapshotLocalData.VersionMeta resolveBaseVersionMeta(
+ OmSnapshotLocalData toSnapshot,
+ UUID fromSnapshotId) throws IOException {
+ OmMetadataManagerImpl metadataManager =
+ (OmMetadataManagerImpl) ozoneManager.getMetadataManager();
+ // Start walking back from the child snapshot
+ OmSnapshotLocalData child = toSnapshot;
+ int numSnapshotsTraversed = 0;
+ while (numSnapshotsTraversed <= maxSnapshotLimit &&
!child.getPreviousSnapshotId().equals(fromSnapshotId)) {
+ UUID parentId = child.getPreviousSnapshotId();
+ // Load the parent snapshot in the chain
+ child = getSnapshotLocalData(
+ getSnapshotInfo(ozoneManager,
+ metadataManager.getSnapshotChainManager(),
+ parentId));
+ numSnapshotsTraversed++;
+ }
+ if (numSnapshotsTraversed > maxSnapshotLimit) {
+ LOG.error("Exceeded the traversal limit of {} while finding the
VersionMeta of the fromSnapshot : {}" +
+ " that the toSnapshot was built on.", maxSnapshotLimit,
fromSnapshotId);
+ return null;
+ }
+ SnapshotInfo snapshotInfo =
+ getSnapshotInfo(ozoneManager,
metadataManager.getSnapshotChainManager(), fromSnapshotId);
+ OmSnapshotLocalData fromSnapshot = getSnapshotLocalData(snapshotInfo);
+ // Get the version that the child was built from
+ OmSnapshotLocalData.VersionMeta childVersionMeta =
child.getVersionSstFileInfos().get(child.getVersion());
Review Comment:
This logic of finding childVersionMeta is wrong. We need to update the
version inside the loop.
##########
hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/SnapshotDiffManager.java:
##########
@@ -1180,6 +1199,37 @@ Set<String> getDeltaFiles(OmSnapshot fromSnapshot,
// TODO: [SNAPSHOT] Refactor the parameter list
Optional<Set<String>> deltaFiles = Optional.empty();
+ OmSnapshotLocalData fromSnapshotLocalData = getSnapshotLocalData(fsInfo);
+ int fromSnapshotVersion = fromSnapshotLocalData.getVersion();
+ OmSnapshotLocalData toSnapshotLocalData = getSnapshotLocalData(tsInfo);
+ int toSnapshotVersion = toSnapshotLocalData.getVersion();
+
+ try {
+ if (fromSnapshotVersion > 0 && toSnapshotVersion > 0) {
Review Comment:
We should not check both. Just checking toSnapshotVersion should be good
enough as the defrag service would always run from the beginning of the chain
##########
hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/SnapshotDiffManager.java:
##########
@@ -1180,6 +1199,37 @@ Set<String> getDeltaFiles(OmSnapshot fromSnapshot,
// TODO: [SNAPSHOT] Refactor the parameter list
Optional<Set<String>> deltaFiles = Optional.empty();
+ OmSnapshotLocalData fromSnapshotLocalData = getSnapshotLocalData(fsInfo);
+ int fromSnapshotVersion = fromSnapshotLocalData.getVersion();
+ OmSnapshotLocalData toSnapshotLocalData = getSnapshotLocalData(tsInfo);
+ int toSnapshotVersion = toSnapshotLocalData.getVersion();
+
+ try {
+ if (fromSnapshotVersion > 0 && toSnapshotVersion > 0) {
+ // both snapshots are defragmented, To calculate snap-diff, we can
simply compare the
+ // SST files contained in OmSnapshotLocalData instances of both these
and get the delta files
+ OmSnapshotLocalData.VersionMeta toSnapVersionMeta =
+
toSnapshotLocalData.getVersionSstFileInfos().get(toSnapshotVersion);
Review Comment:
Let's create a function for this in OmSnapshotLocalData
##########
hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/SnapshotDiffManager.java:
##########
@@ -1223,6 +1273,81 @@ Set<String> getDeltaFiles(OmSnapshot fromSnapshot,
toSnapshot.getSnapshotTableKey()));
}
+ /**
+ * Resolve the VersionMeta of the ancestor snapshot (fromSnapshotId)
+ * that the given snapshot (toSnapshot) was built on.
+ * Traverses the snapshot chain backwards using prevSnapId.
+ *
+ * @param toSnapshot the target snapshot.
+ * @param fromSnapshotId UUID of the source snapshot.
+ * @return the resolved VersionMeta of the source that was used to build the
target.
+ */
+ private OmSnapshotLocalData.VersionMeta resolveBaseVersionMeta(
+ OmSnapshotLocalData toSnapshot,
+ UUID fromSnapshotId) throws IOException {
+ OmMetadataManagerImpl metadataManager =
+ (OmMetadataManagerImpl) ozoneManager.getMetadataManager();
+ // Start walking back from the child snapshot
+ OmSnapshotLocalData child = toSnapshot;
+ int numSnapshotsTraversed = 0;
+ while (numSnapshotsTraversed <= maxSnapshotLimit &&
!child.getPreviousSnapshotId().equals(fromSnapshotId)) {
+ UUID parentId = child.getPreviousSnapshotId();
+ // Load the parent snapshot in the chain
+ child = getSnapshotLocalData(
+ getSnapshotInfo(ozoneManager,
+ metadataManager.getSnapshotChainManager(),
+ parentId));
+ numSnapshotsTraversed++;
Review Comment:
```suggestion
resolvedChildVersionMeta =
child.getVersionMeta(resolvedChildVersionMeta.getPreviousSnapshotVersion());
numSnapshotsTraversed++;
```
##########
hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/SnapshotDiffManager.java:
##########
@@ -1223,6 +1273,81 @@ Set<String> getDeltaFiles(OmSnapshot fromSnapshot,
toSnapshot.getSnapshotTableKey()));
}
+ /**
+ * Resolve the VersionMeta of the ancestor snapshot (fromSnapshotId)
+ * that the given snapshot (toSnapshot) was built on.
+ * Traverses the snapshot chain backwards using prevSnapId.
+ *
+ * @param toSnapshot the target snapshot.
+ * @param fromSnapshotId UUID of the source snapshot.
+ * @return the resolved VersionMeta of the source that was used to build the
target.
+ */
+ private OmSnapshotLocalData.VersionMeta resolveBaseVersionMeta(
+ OmSnapshotLocalData toSnapshot,
+ UUID fromSnapshotId) throws IOException {
+ OmMetadataManagerImpl metadataManager =
+ (OmMetadataManagerImpl) ozoneManager.getMetadataManager();
+ // Start walking back from the child snapshot
+ OmSnapshotLocalData child = toSnapshot;
+ int numSnapshotsTraversed = 0;
Review Comment:
```suggestion
int numSnapshotsTraversed = 0;
VersionMeta resolvedChildVersionMeta =
child.getVersionMeta(childVersion.getVersion());
```
##########
hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/SnapshotDiffManager.java:
##########
@@ -1223,6 +1273,81 @@ Set<String> getDeltaFiles(OmSnapshot fromSnapshot,
toSnapshot.getSnapshotTableKey()));
}
+ /**
+ * Resolve the VersionMeta of the ancestor snapshot (fromSnapshotId)
+ * that the given snapshot (toSnapshot) was built on.
+ * Traverses the snapshot chain backwards using prevSnapId.
+ *
+ * @param toSnapshot the target snapshot.
+ * @param fromSnapshotId UUID of the source snapshot.
+ * @return the resolved VersionMeta of the source that was used to build the
target.
+ */
+ private OmSnapshotLocalData.VersionMeta resolveBaseVersionMeta(
+ OmSnapshotLocalData toSnapshot,
+ UUID fromSnapshotId) throws IOException {
+ OmMetadataManagerImpl metadataManager =
+ (OmMetadataManagerImpl) ozoneManager.getMetadataManager();
+ // Start walking back from the child snapshot
+ OmSnapshotLocalData child = toSnapshot;
+ int numSnapshotsTraversed = 0;
+ while (numSnapshotsTraversed <= maxSnapshotLimit &&
!child.getPreviousSnapshotId().equals(fromSnapshotId)) {
+ UUID parentId = child.getPreviousSnapshotId();
+ // Load the parent snapshot in the chain
+ child = getSnapshotLocalData(
+ getSnapshotInfo(ozoneManager,
+ metadataManager.getSnapshotChainManager(),
+ parentId));
+ numSnapshotsTraversed++;
+ }
+ if (numSnapshotsTraversed > maxSnapshotLimit) {
Review Comment:
Let us not have this max snapshot limit loop condition. In the worst case we
are going to support only maximum of 64k snapshots in the chain.
##########
hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/SnapshotDiffManager.java:
##########
@@ -1223,6 +1273,81 @@ Set<String> getDeltaFiles(OmSnapshot fromSnapshot,
toSnapshot.getSnapshotTableKey()));
}
+ /**
+ * Resolve the VersionMeta of the ancestor snapshot (fromSnapshotId)
+ * that the given snapshot (toSnapshot) was built on.
+ * Traverses the snapshot chain backwards using prevSnapId.
+ *
+ * @param toSnapshot the target snapshot.
+ * @param fromSnapshotId UUID of the source snapshot.
+ * @return the resolved VersionMeta of the source that was used to build the
target.
+ */
+ private OmSnapshotLocalData.VersionMeta resolveBaseVersionMeta(
+ OmSnapshotLocalData toSnapshot,
+ UUID fromSnapshotId) throws IOException {
+ OmMetadataManagerImpl metadataManager =
+ (OmMetadataManagerImpl) ozoneManager.getMetadataManager();
+ // Start walking back from the child snapshot
+ OmSnapshotLocalData child = toSnapshot;
+ int numSnapshotsTraversed = 0;
+ while (numSnapshotsTraversed <= maxSnapshotLimit &&
!child.getPreviousSnapshotId().equals(fromSnapshotId)) {
+ UUID parentId = child.getPreviousSnapshotId();
+ // Load the parent snapshot in the chain
+ child = getSnapshotLocalData(
+ getSnapshotInfo(ozoneManager,
+ metadataManager.getSnapshotChainManager(),
+ parentId));
+ numSnapshotsTraversed++;
+ }
+ if (numSnapshotsTraversed > maxSnapshotLimit) {
+ LOG.error("Exceeded the traversal limit of {} while finding the
VersionMeta of the fromSnapshot : {}" +
+ " that the toSnapshot was built on.", maxSnapshotLimit,
fromSnapshotId);
+ return null;
+ }
+ SnapshotInfo snapshotInfo =
+ getSnapshotInfo(ozoneManager,
metadataManager.getSnapshotChainManager(), fromSnapshotId);
+ OmSnapshotLocalData fromSnapshot = getSnapshotLocalData(snapshotInfo);
+ // Get the version that the child was built from
+ OmSnapshotLocalData.VersionMeta childVersionMeta =
child.getVersionSstFileInfos().get(child.getVersion());
+ int versionUsedWhenBuildingChild =
childVersionMeta.getPreviousSnapshotVersion();
Review Comment:
```suggestion
return resolvedChildVersionMeta;
```
##########
hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/SnapshotDiffManager.java:
##########
@@ -1180,6 +1199,37 @@ Set<String> getDeltaFiles(OmSnapshot fromSnapshot,
// TODO: [SNAPSHOT] Refactor the parameter list
Optional<Set<String>> deltaFiles = Optional.empty();
+ OmSnapshotLocalData fromSnapshotLocalData = getSnapshotLocalData(fsInfo);
+ int fromSnapshotVersion = fromSnapshotLocalData.getVersion();
+ OmSnapshotLocalData toSnapshotLocalData = getSnapshotLocalData(tsInfo);
+ int toSnapshotVersion = toSnapshotLocalData.getVersion();
+
+ try {
+ if (fromSnapshotVersion > 0 && toSnapshotVersion > 0) {
+ // both snapshots are defragmented, To calculate snap-diff, we can
simply compare the
+ // SST files contained in OmSnapshotLocalData instances of both these
and get the delta files
+ OmSnapshotLocalData.VersionMeta toSnapVersionMeta =
+
toSnapshotLocalData.getVersionSstFileInfos().get(toSnapshotVersion);
+ // get the source snapshot SST files (versionMeta) corresponding to
target snapshot
+ OmSnapshotLocalData.VersionMeta fromSnapVersionMeta =
+ resolveBaseVersionMeta(toSnapshotLocalData,
fromSnapshot.getSnapshotID());
+ // Calculate diff files using helper method
+ if (toSnapVersionMeta == null) {
+ String errMsg =
+ "Cannot find corresponding version of from snapshot " +
fromSnapshotVersion + " from " + tsInfo;
+ LOG.error(errMsg);
+ throw new IOException(errMsg);
+ }
+ List<String> diffFiles = calculateDiffFiles(fromSnapVersionMeta,
toSnapVersionMeta);
+ return OmSnapshotUtils.getSSTDiffListWithFullPath(diffFiles,
+
OmSnapshotManager.getSnapshotPath(ozoneManager.getMetadataManager(),
fsInfo).toString(),
+
OmSnapshotManager.getSnapshotPath(ozoneManager.getMetadataManager(),
tsInfo).toString(), diffDir);
+ }
+ } catch (Exception e) {
+ LOG.error("Failed to calculate snap-diff between fromSnapshot : {} ,
toSnapshot: {} via optimal method," +
+ "Falling back to other methods", fsInfo, tsInfo, e);
+ }
+
// Check if compaction DAG is available, use that if so
if (differ != null && fsInfo != null && tsInfo != null && !useFullDiff) {
Review Comment:
We need rocksdb checkpoint differ to also use the SnapshotLocalMetadata
instead of the rocksdb instance itself.
There are 3 possible conditions:
1. fromSnapshot is defragged and toSNapshot Defragged
2. fromSnapshot is not defragged and toSnapshot not defragged
3. fromSnapshot is Defragged and toSnapshot not Defragged
4. fromSnapshot is not Defragged and toSnapshot Defragged(This is not
possible.)
This patch covers only the first condition so far. 2 and 3 condition should
fall back to dag based diff by using both version 0's sst files to compute diff.
Effectively logic is :
```
if (toSnapshot.getVersion() > 0) {
perfromFullDiff(fromSnapshot(version=correspoding version from traversing
linked list), toSnapshot(version=toSnapshotVersion));
} else {
if (Dag available) {
performDagDiff(fromSnapshot(version=0), toSnapshot(version=0));
} else {
peformFullDiff(fromSnapshot(version=0), toSnapshot(version=0))
}
}
}
```
##########
hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/SnapshotDiffManager.java:
##########
@@ -1223,6 +1265,70 @@ Set<String> getDeltaFiles(OmSnapshot fromSnapshot,
toSnapshot.getSnapshotTableKey()));
}
+ /**
+ * Resolve the VersionMeta of the ancestor snapshot (fromSnapshotId)
+ * that the given snapshot (toSnapshot) was built on.
+ *
+ * Traverses the snapshot chain backwards using prevSnapId.
+ */
+ private OmSnapshotLocalData.VersionMeta resolveBaseVersionMeta(
+ OmSnapshotLocalData toSnapshot,
+ UUID fromSnapshotId) throws IOException {
+ OmMetadataManagerImpl metadataManager =
+ (OmMetadataManagerImpl) ozoneManager.getMetadataManager();
+ // Start walking back from the child snapshot
+ OmSnapshotLocalData child = toSnapshot;
+ while (!child.getPreviousSnapshotId().equals(fromSnapshotId)) {
+ UUID parentId = child.getPreviousSnapshotId();
+ // Load the parent snapshot in the chain
+ child = getSnapshotLocalData(
+ getSnapshotInfo(ozoneManager,
+ metadataManager.getSnapshotChainManager(),
+ parentId));
+ }
+ SnapshotInfo snapshotInfo =
+ getSnapshotInfo(ozoneManager,
metadataManager.getSnapshotChainManager(), fromSnapshotId);
+ OmSnapshotLocalData fromSnapshot = getSnapshotLocalData(snapshotInfo);
+ // Get the version that the child was built from
+ OmSnapshotLocalData.VersionMeta childVersionMeta =
child.getVersionSstFileInfos().get(child.getVersion());
+ int versionUsedWhenBuildingChild =
childVersionMeta.getPreviousSnapshotVersion();
+ return
fromSnapshot.getVersionSstFileInfos().get(versionUsedWhenBuildingChild);
Review Comment:
This should not happen
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