mcvsubbu commented on a change in pull request #7969:
URL: https://github.com/apache/pinot/pull/7969#discussion_r778280965
##########
File path:
pinot-segment-local/src/main/java/org/apache/pinot/segment/local/segment/index/loader/LoaderUtils.java
##########
@@ -161,4 +160,36 @@ public static void reloadFailureRecovery(File indexDir)
FileUtils.forceDelete(segmentTempDir);
}
}
+
+ public static void createBackup(File indexDir)
+ throws IOException {
+ if (!indexDir.exists()) {
Review comment:
Why has this check been added?
##########
File path:
pinot-segment-local/src/main/java/org/apache/pinot/segment/local/segment/index/loader/LoaderUtils.java
##########
@@ -161,4 +160,36 @@ public static void reloadFailureRecovery(File indexDir)
FileUtils.forceDelete(segmentTempDir);
}
}
+
+ public static void createBackup(File indexDir)
+ throws IOException {
+ 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);
+ // Copy the backup dir back to proceed.
+ FileUtils.copyDirectory(segmentBackupDir, indexDir);
Review comment:
We used to rename the current directory and reload. Can you clarify why
we have changed it to copy the segment instead?
##########
File path:
pinot-core/src/main/java/org/apache/pinot/core/data/manager/BaseTableDataManager.java
##########
@@ -275,53 +278,23 @@ public void addSegmentError(String segmentName,
SegmentErrorInfo segmentErrorInf
@Override
public void reloadSegment(String segmentName, IndexLoadingConfig
indexLoadingConfig, SegmentZKMetadata zkMetadata,
- SegmentMetadata localMetadata, @Nullable Schema schema, boolean
forceDownload)
+ SegmentMetadata segmentMetadata, @Nullable Schema schema, boolean
forceDownload)
throws Exception {
- File indexDir = localMetadata.getIndexDir();
- Preconditions.checkState(indexDir.isDirectory(), "Index directory: %s is
not a directory", indexDir);
-
- File parentFile = indexDir.getParentFile();
- File segmentBackupDir =
- new File(parentFile, indexDir.getName() +
CommonConstants.Segment.SEGMENT_BACKUP_DIR_SUFFIX);
-
+ File indexDir = getSegmentDataDir(segmentName);
+ // Create backup dir to make segment reloading atomic for local tier
backend.
+ LoaderUtils.createBackup(indexDir);
try {
- // 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
-
- // 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);
-
- // Download from remote or copy from local backup directory into index
directory,
- // and then continue to load the segment from index directory.
- boolean shouldDownload = forceDownload || !hasSameCRC(zkMetadata,
localMetadata);
- if (shouldDownload && allowDownload(segmentName, zkMetadata)) {
- if (forceDownload) {
- LOGGER.info("Segment: {} of table: {} is forced to download",
segmentName, _tableNameWithType);
- } else {
- LOGGER.info("Download segment:{} of table: {} as local crc: {}
mismatches remote crc: {}", segmentName,
- _tableNameWithType, localMetadata.getCrc(), zkMetadata.getCrc());
- }
- indexDir = downloadSegment(segmentName, zkMetadata);
+ boolean shouldDownloadRawSegment = forceDownload ||
!hasSameCRC(zkMetadata, segmentMetadata);
+ if (shouldDownloadRawSegment && allowDownloadRawSegment(segmentName,
zkMetadata)) {
+ downloadRawSegmentAndProcess(segmentName, indexLoadingConfig,
zkMetadata, schema);
Review comment:
Can you clarify why we download from a "tier" (I assume this to mean a
peer storage server that already hosts the segment), as opposed to always
downloading from the master and keep things simple?
##########
File path:
pinot-core/src/main/java/org/apache/pinot/core/data/manager/BaseTableDataManager.java
##########
@@ -275,53 +278,23 @@ public void addSegmentError(String segmentName,
SegmentErrorInfo segmentErrorInf
@Override
public void reloadSegment(String segmentName, IndexLoadingConfig
indexLoadingConfig, SegmentZKMetadata zkMetadata,
- SegmentMetadata localMetadata, @Nullable Schema schema, boolean
forceDownload)
+ SegmentMetadata segmentMetadata, @Nullable Schema schema, boolean
forceDownload)
throws Exception {
- File indexDir = localMetadata.getIndexDir();
- Preconditions.checkState(indexDir.isDirectory(), "Index directory: %s is
not a directory", indexDir);
-
- File parentFile = indexDir.getParentFile();
- File segmentBackupDir =
- new File(parentFile, indexDir.getName() +
CommonConstants.Segment.SEGMENT_BACKUP_DIR_SUFFIX);
-
+ File indexDir = getSegmentDataDir(segmentName);
+ // Create backup dir to make segment reloading atomic for local tier
backend.
+ LoaderUtils.createBackup(indexDir);
try {
- // 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
-
- // 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);
-
- // Download from remote or copy from local backup directory into index
directory,
- // and then continue to load the segment from index directory.
- boolean shouldDownload = forceDownload || !hasSameCRC(zkMetadata,
localMetadata);
- if (shouldDownload && allowDownload(segmentName, zkMetadata)) {
- if (forceDownload) {
- LOGGER.info("Segment: {} of table: {} is forced to download",
segmentName, _tableNameWithType);
- } else {
- LOGGER.info("Download segment:{} of table: {} as local crc: {}
mismatches remote crc: {}", segmentName,
- _tableNameWithType, localMetadata.getCrc(), zkMetadata.getCrc());
- }
- indexDir = downloadSegment(segmentName, zkMetadata);
+ boolean shouldDownloadRawSegment = forceDownload ||
!hasSameCRC(zkMetadata, segmentMetadata);
+ if (shouldDownloadRawSegment && allowDownloadRawSegment(segmentName,
zkMetadata)) {
+ downloadRawSegmentAndProcess(segmentName, indexLoadingConfig,
zkMetadata, schema);
} else {
- LOGGER.info("Reload the local copy of segment: {} of table: {}",
segmentName, _tableNameWithType);
- FileUtils.copyDirectory(segmentBackupDir, indexDir);
+ downloadTierSegmentAndProcess(segmentName, indexLoadingConfig, schema);
}
-
- // Load from index directory and replace the old segment in memory.
- addSegment(ImmutableSegmentLoader.load(indexDir, indexLoadingConfig,
schema));
-
- // Rename segment backup directory to segment temporary directory
(atomic)
- // The reason to first rename then delete is that, 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
- File segmentTempDir = new File(parentFile, 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);
+ // Remove backup dir to mark the completion of reloading for local tier
backend.
+ LoaderUtils.removeBackup(indexDir);
Review comment:
Can we keep the comments and renaming code here? Moving this to a method
called "removeBackup" in a different class may lead to future modifications
that may not keep the semantics of rename and remove (yes, you have moved the
comments as well, but I think it is better to keep it local).
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