klsince commented on a change in pull request #7969:
URL: https://github.com/apache/pinot/pull/7969#discussion_r780526797
##########
File path:
pinot-core/src/main/java/org/apache/pinot/core/data/manager/BaseTableDataManager.java
##########
@@ -480,12 +426,138 @@ File getSegmentDataDir(String segmentName) {
return new File(_indexDir, 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;
+ }
+ File segmentTempDir = new File(parentDir, indexDir.getName() +
CommonConstants.Segment.SEGMENT_TEMP_DIR_SUFFIX);
+ // Rename segment backup directory to segment temporary directory (atomic).
+ 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 = tryGetSegmentDirectory(segmentName,
indexLoadingConfig);
+ SegmentMetadataImpl segmentMetadata = (segmentDirectory == null) ? null :
segmentDirectory.getSegmentMetadata();
+
+ // If the segment doesn't exist on server or its CRC has changed, then we
+ // need to fall back to download the segment from deep store to load it.
+ if (segmentMetadata == null) {
+ LOGGER.info("Segment: {} of table: {} does not exist", segmentName,
_tableNameWithType);
+ return false;
+ }
+ if (!hasSameCRC(zkMetadata, segmentMetadata)) {
+ LOGGER.info("Segment: {} of table: {} has crc change from: {} to: {}",
segmentName, _tableNameWithType,
+ segmentMetadata.getCrc(), zkMetadata.getCrc());
+ return false;
+ }
+
+ try {
+ // If the segment is still kept by the server, then we can
+ // either load it directly if it's still consistent with latest table
config and schema;
+ // or reprocess it to reflect latest table config and schema before
loading.
+ Schema schema = ZKMetadataProvider.getTableSchema(_propertyStore,
_tableNameWithType);
+ if (!ImmutableSegmentLoader.needPreprocess(segmentDirectory,
indexLoadingConfig, schema)) {
+ LOGGER.info("Segment: {} of table: {} is consistent with latest table
config and schema", segmentName,
+ _tableNameWithType);
+ } else {
+ LOGGER.info("Segment: {} of table: {} needs reprocess to reflect
latest table config and schema", segmentName,
+ _tableNameWithType);
+ segmentDirectory.copyTo(indexDir);
+ // Close the stale SegmentDirectory object and recreate it with
reprocessed segment.
+ closeSegmentDirectoryQuietly(segmentDirectory);
+ ImmutableSegmentLoader.preprocess(indexDir, indexLoadingConfig,
schema);
+ segmentDirectory = getSegmentDirectory(segmentName,
indexLoadingConfig);
+ }
+ ImmutableSegment segment = ImmutableSegmentLoader.load(segmentDirectory,
indexLoadingConfig, schema);
+ addSegment(segment);
+ LOGGER.info("Loaded existing segment: {} of table: {} with crc: {}",
segmentName, _tableNameWithType,
+ zkMetadata.getCrc());
+ return true;
+ } catch (Exception e) {
+ LOGGER.error("Failed to load existing segment: {} of table: {} with crc:
{}", segmentName, _tableNameWithType, e);
+ closeSegmentDirectoryQuietly(segmentDirectory);
+ return false;
+ }
+ }
+
+ private SegmentDirectory tryGetSegmentDirectory(String segmentName,
IndexLoadingConfig indexLoadingConfig) {
+ try {
+ return getSegmentDirectory(segmentName, indexLoadingConfig);
+ } catch (Exception e) {
+ LOGGER.warn("Attempt to get SegmentDirectory for segment: {} of table:
{} failed with error: {}", segmentName,
+ _tableNameWithType, e.getMessage());
+ return null;
+ }
+ }
+
+ private SegmentDirectory getSegmentDirectory(String segmentName,
IndexLoadingConfig indexLoadingConfig)
Review comment:
I'll rethink the method names: this one gets SegmentDirectory object;
the getSegmentDataDir composes seg dir path.
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