Parth-Brahmbhatt commented on a change in pull request #388: Handle rollback in
snapshot expiration
URL: https://github.com/apache/incubator-iceberg/pull/388#discussion_r317838958
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File path: core/src/main/java/org/apache/iceberg/RemoveSnapshots.java
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@@ -120,56 +123,128 @@ public void commit() {
}
});
- LOG.info("Committed snapshot changes; cleaning up expired manifests and
data files.");
+ cleanExpiredSnapshots();
+ }
+ private void cleanExpiredSnapshots() {
// clean up the expired snapshots:
// 1. Get a list of the snapshots that were removed
// 2. Delete any data files that were deleted by those snapshots and are
not in the table
// 3. Delete any manifests that are no longer used by current snapshots
// 4. Delete the manifest lists
+ TableMetadata current = ops.refresh();
+
+ Set<Long> validIds = Sets.newHashSet();
+ for (Snapshot snapshot : current.snapshots()) {
+ validIds.add(snapshot.snapshotId());
+ }
+
+ Set<Long> expiredIds = Sets.newHashSet();
+ for (Snapshot snapshot : base.snapshots()) {
+ long snapshotId = snapshot.snapshotId();
+ if (!validIds.contains(snapshotId)) {
+ // the snapshot was expired
+ LOG.info("Expired snapshot: {}", snapshot);
+ expiredIds.add(snapshotId);
+ }
+ }
+
+ if (expiredIds.isEmpty()) {
+ // if no snapshots were expired, skip cleanup
+ return;
+ }
+
+ LOG.info("Committed snapshot changes; cleaning up expired manifests and
data files.");
+
+ cleanExpiredFiles(current.snapshots(), validIds, expiredIds);
+ }
+
+ @SuppressWarnings("checkstyle:CyclomaticComplexity")
+ private void cleanExpiredFiles(List<Snapshot> snapshots, Set<Long> validIds,
Set<Long> expiredIds) {
// Reads and deletes are done using
Tasks.foreach(...).suppressFailureWhenFinished to complete
// as much of the delete work as possible and avoid orphaned data or
manifest files.
- TableMetadata current = ops.refresh();
- Set<Long> currentIds = Sets.newHashSet();
- Set<ManifestFile> currentManifests = Sets.newHashSet();
- for (Snapshot snapshot : current.snapshots()) {
- currentIds.add(snapshot.snapshotId());
- currentManifests.addAll(snapshot.manifests());
+ // this is the set of ancestors of the current table state. when removing
snapshots, this must
+ // only remove files that were deleted in an ancestor of the current table
state to avoid
+ // physically deleting files that were logically deleted in a commit that
was rolled back.
+ Set<Long> ancestorIds =
Sets.newHashSet(SnapshotUtil.ancestorIds(base.currentSnapshot(),
base::snapshot));
+
+ Set<String> validManifests = Sets.newHashSet();
+ Set<String> manifestsToScan = Sets.newHashSet();
+ for (Snapshot snapshot : snapshots) {
+ validIds.add(snapshot.snapshotId());
Review comment:
this seems unnecessary, the passed in validIds should already have these
snapshotIds.
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