branch-4.0: [fix](cloud) checkpoint save cloud tablet stats to image (#60705)

[mymeiyi]

pick #60705

[Thearas]

Thank you for your contribution to Apache Doris.
Don't know what should be done next? See How to process your PR.

Please clearly describe your PR:

1. What problem was fixed (it's best to include specific error reporting information). How it was fixed.
2. Which behaviors were modified. What was the previous behavior, what is it now, why was it modified, and what possible impacts might there be.
3. What features were added. Why was this function added?
4. Which code was refactored and why was this part of the code refactored?
5. Which functions were optimized and what is the difference before and after the optimization?

[mymeiyi]

run buildall

[Copilot]

Pull request overview

This PR backports a cloud-mode fix to ensure checkpoint images remain fresh enough to carry up-to-date cloud tablet/replica statistics, and adds logic to post-process checkpoint metadata using the serving FE’s latest stats.

Changes:

• Track latest image file timestamp and trigger checkpoint in cloud mode when the image is older than a configurable threshold.
• Post-process checkpoint metadata in cloud mode to copy tablet/replica stats from the serving Env into the checkpoint Env before saving the image.
• Persist additional cloud/replica stat fields into the image via @SerializedName, and initialize cloud table stats on FE start when empty.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
fe/fe-core/src/main/java/org/apache/doris/persist/Storage.java	Track latest image “create time” (via file mtime) to support staleness-based checkpoint triggering.
fe/fe-core/src/main/java/org/apache/doris/master/Checkpoint.java	Add cloud staleness trigger and post-process cloud metadata to copy stats into the checkpoint image.
fe/fe-core/src/main/java/org/apache/doris/cloud/catalog/CloudReplica.java	Persist cloud replica tablet-stat timing fields into the image using short serialized names.
fe/fe-core/src/main/java/org/apache/doris/catalog/Replica.java	Persist segmentCount / rowsetCount into the image via @SerializedName.
fe/fe-core/src/main/java/org/apache/doris/catalog/CloudTabletStatMgr.java	On startup, initialize table stats from image-loaded tablet stats when current stats list is empty.
fe/fe-common/src/main/java/org/apache/doris/common/Config.java	Add cloud checkpoint image staleness threshold config.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

postProcessCloudMetadata() traverses servingEnv metadata (tables/partitions/indexes/tablets) without taking the usual read locks. Partition’s index maps are plain HashMaps, so concurrent DDL/rollup updates on the serving catalog can lead to inconsistent reads or ConcurrentModificationException during checkpoint. Consider acquiring servingOlapTable.readLock() (and releasing in finally) while you resolve partitions/index/tablet/replica lookups (or otherwise snapshot the needed structures under lock).

Suggested change

	for (Partition partition : partitions) {
	Partition servingPartition = servingOlapTable.getPartition(partition.getId());
	if (servingPartition == null) {
	if (LOG.isDebugEnabled()) {
	LOG.debug("serving partition is null. tableId: {}, partitionId: {}", table.getId(),
	partition.getId());
	}
	continue;
	}
	// set tablet stats
	setTabletStats(table.getId(), partition, servingPartition);
	servingOlapTable.readLock();
	try {
	for (Partition partition : partitions) {
	Partition servingPartition = servingOlapTable.getPartition(partition.getId());
	if (servingPartition == null) {
	if (LOG.isDebugEnabled()) {
	LOG.debug("serving partition is null. tableId: {}, partitionId: {}", table.getId(),
	partition.getId());
	}
	continue;
	}
	// set tablet stats
	setTabletStats(table.getId(), partition, servingPartition);
	}
	} finally {
	servingOlapTable.readUnlock();

[Copilot]

setTabletStats() unconditionally casts both replica and servingReplica to CloudReplica. In cloud mode, the image loader can still deserialize replicas as base Replica (e.g., compatibility subtype LocalReplica or default subtype), so this can throw ClassCastException and fail the whole checkpoint. Please guard with instanceof (and only copy the cloud-specific fields when both sides are CloudReplica), so checkpoint remains best-effort for stats copying.

Suggested change

	CloudReplica cloudReplica = (CloudReplica) replica;
	CloudReplica servingCloudReplica = (CloudReplica) servingReplica;
	cloudReplica.setStatsIntervalIndex(servingCloudReplica.getStatsIntervalIndex());
	cloudReplica.setLastGetTabletStatsTime(servingCloudReplica.getLastGetTabletStatsTime());
	if (replica instanceof CloudReplica && servingReplica instanceof CloudReplica) {
	CloudReplica cloudReplica = (CloudReplica) replica;
	CloudReplica servingCloudReplica = (CloudReplica) servingReplica;
	cloudReplica.setStatsIntervalIndex(servingCloudReplica.getStatsIntervalIndex());
	cloudReplica.setLastGetTabletStatsTime(servingCloudReplica.getLastGetTabletStatsTime());
	}

[hello-stephen]

FE UT Coverage Report

Increment line coverage 6.59% (6/91) 🎉
Increment coverage report
Complete coverage report