Fix ReclaimedSpaceViaDeletes stats incorrect problem.

[horizonzy]

Descriptions of the changes in this PR:

bookkeeper/bookkeeper-server/src/main/java/org/apache/bookkeeper/bookie/GarbageCollectorThread.java

Lines 487 to 517 in a6387d1

	private void doGcEntryLogs() throws EntryLogMetadataMapException {
	// Get a cumulative count, don't update until complete
	AtomicLong totalEntryLogSizeAcc = new AtomicLong(0L);
	// Loop through all of the entry logs and remove the non-active ledgers.
	entryLogMetaMap.forEach((entryLogId, meta) -> {
	try {
	boolean modified = removeIfLedgerNotExists(meta);
	if (meta.isEmpty()) {
	// This means the entry log is not associated with any active
	// ledgers anymore.
	// We can remove this entry log file now.
	LOG.info("Deleting entryLogId {} as it has no active ledgers!", entryLogId);
	removeEntryLog(entryLogId);
	gcStats.getReclaimedSpaceViaDeletes().addCount(meta.getTotalSize());
	} else if (modified) {
	// update entryLogMetaMap only when the meta modified.
	entryLogMetaMap.put(meta.getEntryLogId(), meta);
	}
	} catch (EntryLogMetadataMapException e) {
	// Ignore and continue because ledger will not be cleaned up
	// from entry-logger in this pass and will be taken care in next
	// schedule task
	LOG.warn("Failed to remove ledger from entry-log metadata {}", entryLogId, e);
	}
	totalEntryLogSizeAcc.getAndAdd(meta.getRemainingSize());
	});
	this.totalEntryLogSize = totalEntryLogSizeAcc.get();
	this.numActiveEntryLogs = entryLogMetaMap.size();
	}

At line 501, increases getReclaimedSpaceViaDeletes stats.

bookkeeper/bookkeeper-server/src/main/java/org/apache/bookkeeper/bookie/GarbageCollectorThread.java

Lines 734 to 767 in a6387d1

	protected void extractMetaFromEntryLogs() throws EntryLogMetadataMapException {
	for (long entryLogId : entryLogger.getFlushedLogIds()) {
	// Comb the current entry log file if it has not already been extracted.
	if (entryLogMetaMap.containsKey(entryLogId)) {
	continue;
	}
	// check whether log file exists or not
	// if it doesn't exist, this log file might have been garbage collected.
	if (!entryLogger.logExists(entryLogId)) {
	continue;
	}
	LOG.info("Extracting entry log meta from entryLogId: {}", entryLogId);
	try {
	// Read through the entry log file and extract the entry log meta
	EntryLogMetadata entryLogMeta = entryLogger.getEntryLogMetadata(entryLogId, throttler);
	removeIfLedgerNotExists(entryLogMeta);
	if (entryLogMeta.isEmpty()) {
	LOG.info("Entry log file {} is empty, delete it from disk.", Long.toHexString(entryLogId));
	entryLogger.removeEntryLog(entryLogId);
	// remove it from entrylogmetadata-map if it is present in
	// the map
	entryLogMetaMap.remove(entryLogId);
	} else {
	entryLogMetaMap.put(entryLogId, entryLogMeta);
	}
	} catch (IOException e) {
	LOG.warn("Premature exception when processing " + entryLogId
	+ " recovery will take care of the problem", e);
	}
	}
	}

But at line 755, it didn't increases getReclaimedSpaceViaDeletes stats.

[horizonzy]

rerun failure checks

[hangc0276]

We don't need to update the stats because the entryLogMeta is empty and the entryLogMeta.getTotalSize() will be 0

[horizonzy]

bookkeeper/bookkeeper-server/src/main/java/org/apache/bookkeeper/bookie/EntryLogMetadata.java

Lines 94 to 102 in ceba605

	public void removeLedgerIf(LongPredicate predicate) {
	ledgersMap.removeIf((ledgerId, size) -> {
	boolean shouldRemove = predicate.test(ledgerId);
	if (shouldRemove) {
	remainingSize -= size;
	}
	return shouldRemove;
	});
	}

,
it only reduces the remainingSize, the totalSize won't be reduce to 0.

[hangc0276]

Oh sorry, it's my mistake.

[wenbingshen]

Nice Catch!