snleee commented on a change in pull request #7969:
URL: https://github.com/apache/pinot/pull/7969#discussion_r781531660
##########
File path:
pinot-core/src/main/java/org/apache/pinot/core/data/manager/BaseTableDataManager.java
##########
@@ -277,49 +282,36 @@ public void addSegmentError(String segmentName,
SegmentErrorInfo segmentErrorInf
public void reloadSegment(String segmentName, IndexLoadingConfig
indexLoadingConfig, SegmentZKMetadata zkMetadata,
SegmentMetadata localMetadata, @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);
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
+ // Create backup directory to handle failure of segment reloading.
Review comment:
Add more information to the comment that we are actually `renaming` the
`indexDir` to `indexBackupDir`.
##########
File path:
pinot-core/src/main/java/org/apache/pinot/core/data/manager/BaseTableDataManager.java
##########
@@ -277,49 +282,36 @@ public void addSegmentError(String segmentName,
SegmentErrorInfo segmentErrorInf
public void reloadSegment(String segmentName, IndexLoadingConfig
indexLoadingConfig, SegmentZKMetadata zkMetadata,
SegmentMetadata localMetadata, @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);
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
+ // Create backup directory to handle failure of segment reloading.
+ createBackup(indexDir);
- // 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.
+ // Download segment from deep store if CRC changes or forced to download;
+ // otherwise, copy backup directory back to the original index directory.
+ // And then continue to load the segment from the 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,
+ LOGGER.info("Download segment:{} of table: {} as crc changes from:
{} to: {}", segmentName,
_tableNameWithType, localMetadata.getCrc(), zkMetadata.getCrc());
}
indexDir = downloadSegment(segmentName, zkMetadata);
} else {
- LOGGER.info("Reload the local copy of segment: {} of table: {}",
segmentName, _tableNameWithType);
- FileUtils.copyDirectory(segmentBackupDir, indexDir);
+ LOGGER.info("Reload existing segment: {} of table: {}", segmentName,
_tableNameWithType);
+ try (SegmentDirectory segmentDirectory =
initSegmentDirectory(segmentName, indexLoadingConfig)) {
Review comment:
Let's say
indexDir = original segments dir (/segments/table/segment_name)
backupDir = backup dir (/segmetns/table/segment_name.segment.bak)
The previous logic was:
```
1. copy backup dir -> index dir
2. load index dir
```
The current logic looks that:
```
1. copy indexDir -> indexDir (but indexDir is empty so fall back to backup
in `copyTo()` and this makes `backupDir -> indexDir`)
2. load index dir
```
I get the point the the logic is the same; however, I would prefer to see
that you use `indexDir` and `indexBackupDir` variables directly in `reload()`
function to have much better readability. I had to read all the sub-function
details to understand the existing logic. How do you think?
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