mcvsubbu commented on a change in pull request #7969:
URL: https://github.com/apache/pinot/pull/7969#discussion_r783294197
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File path:
pinot-core/src/main/java/org/apache/pinot/core/data/manager/BaseTableDataManager.java
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@@ -493,12 +445,139 @@ protected File getTmpSegmentDataDir(String segmentName) {
return new File(_resourceTmpDir, segmentName);
}
- @VisibleForTesting
- static boolean isNewSegment(SegmentZKMetadata zkMetadata, @Nullable
SegmentMetadata localMetadata) {
- return localMetadata == null || !hasSameCRC(zkMetadata, localMetadata);
+ /**
+ * Create a backup directory to handle failure of segment reloading.
+ * First rename index directory to segment backup directory so that original
segment have all file
+ * descriptors point to the segment backup directory to ensure original
segment serves queries properly.
+ * The original index directory is restored lazily, as depending on the
conditions,
+ * it may be restored from the backup directory or segment downloaded from
deep store.
+ */
+ private void createBackup(File indexDir) {
+ if (!indexDir.exists()) {
+ return;
+ }
+ File parentDir = indexDir.getParentFile();
+ File segmentBackupDir = new File(parentDir, indexDir.getName() +
CommonConstants.Segment.SEGMENT_BACKUP_DIR_SUFFIX);
+ // Rename index directory to segment backup directory (atomic).
+ Preconditions.checkState(indexDir.renameTo(segmentBackupDir),
+ "Failed to rename index directory: %s to segment backup directory:
%s", indexDir, segmentBackupDir);
+ }
+
+ /**
+ * Remove the backup directory to mark the completion of segment reloading.
+ * First rename then delete is as renaming is an atomic operation, but
deleting is not.
+ * When we rename the segment backup directory to segment temporary
directory, we know the reload
+ * already succeeded, so that we can safely delete the segment temporary
directory.
+ */
+ private void removeBackup(File indexDir)
+ throws IOException {
+ File parentDir = indexDir.getParentFile();
+ File segmentBackupDir = new File(parentDir, indexDir.getName() +
CommonConstants.Segment.SEGMENT_BACKUP_DIR_SUFFIX);
+ if (!segmentBackupDir.exists()) {
+ return;
+ }
+ // Rename segment backup directory to segment temporary directory (atomic).
+ File segmentTempDir = new File(parentDir, indexDir.getName() +
CommonConstants.Segment.SEGMENT_TEMP_DIR_SUFFIX);
+ Preconditions.checkState(segmentBackupDir.renameTo(segmentTempDir),
+ "Failed to rename segment backup directory: %s to segment temporary
directory: %s", segmentBackupDir,
+ segmentTempDir);
+ FileUtils.deleteDirectory(segmentTempDir);
+ }
+
+ private boolean tryLoadExistingSegment(String segmentName,
IndexLoadingConfig indexLoadingConfig,
+ SegmentZKMetadata zkMetadata) {
+ // Try to recover the segment from potential segment reloading failure.
+ File indexDir = getSegmentDataDir(segmentName);
+ recoverReloadFailureQuietly(_tableNameWithType, segmentName, indexDir);
+
+ // Creates the SegmentDirectory object to access the segment metadata.
+ // The metadata is null if the segment doesn't exist yet.
+ SegmentDirectory segmentDirectory = tryInitSegmentDirectory(segmentName,
indexLoadingConfig);
Review comment:
Can you verify that we don't see a warning in the normal case of loading
a new segment? It seems to me that the following steps will happen.
addOrReplace() -> tryLoadExistingSegment() -> tryInitSegmentDirectory() ->
initSegmentDirectory()
The last method catches and exception and logs a warning.
There should not be any warnings in the normal case.
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