branch-4.1: pick #61318, #60543, #60705

[mymeiyi]

pick:

1. modify CloudTabletRebalancer and CloudTabletStatMgr to reduce memory ([fix](cloud) modify CloudTabletRebalancer and CloudTabletStatMgr to reduce memory #61318)
2. cloud reduce get_tablet_stats rpc to meta_service ([improve](cloud) cloud reduce get_tablet_stats rpc to meta_service #60543)
3. checkpoint save cloud tablet stats to image ([fix](cloud) checkpoint save cloud tablet stats to image #60705)

[Thearas]

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1. What problem was fixed (it's best to include specific error reporting information). How it was fixed.
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[mymeiyi]

run buildall

[Copilot]

Pull request overview

Backports three cloud-mode improvements to the 4.1 branch to reduce FE memory usage, reduce meta-service get_tablet_stats RPC volume, and ensure cloud tablet stats are preserved/updated via checkpoints and FE-to-FE sync.

Changes:

• Add tablet-id propagation on commit/compaction notifications and use it to mark tablets “active” for faster stats refresh.
• Rework CloudTabletStatMgr to compute/prom-filter top-N table stats once per stats cycle, add an interval-ladder polling strategy, and push active tablet stats from master FE to other FEs.
• Enhance checkpointing to optionally trigger in cloud mode based on image staleness and to copy serving-env tablet stats into the checkpoint image.

Reviewed changes

Copilot reviewed 18 out of 18 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
gensrc/thrift/FrontendService.thrift	Adds tabletIds to commit report requests and introduces FE-to-FE syncCloudTabletStats RPC.
fe/fe-core/src/main/java/org/apache/doris/transaction/GlobalTransactionMgrIface.java	Extends commit callback to accept tabletIds for downstream stats refresh.
fe/fe-core/src/main/java/org/apache/doris/transaction/GlobalTransactionMgr.java	Updates interface implementation signature (no-op in non-cloud mgr).
fe/fe-core/src/main/java/org/apache/doris/service/FrontendServiceImpl.java	Handles tabletIds on commit/compaction report; implements syncCloudTabletStats.
fe/fe-core/src/main/java/org/apache/doris/qe/SessionVariable.java	Adds session var to force tablet-stats sync via proc-tablets path.
fe/fe-core/src/main/java/org/apache/doris/persist/Storage.java	Tracks latest image mtime to support “stale image” checkpoint triggering.
fe/fe-core/src/main/java/org/apache/doris/metric/PrometheusMetricVisitor.java	Uses CloudTabletStatMgr precomputed totals/top-N instead of recomputing per scrape.
fe/fe-core/src/main/java/org/apache/doris/master/Checkpoint.java	Adds stale-image-based checkpoint trigger (cloud) + copies serving-env tablet stats into checkpoint image.
fe/fe-core/src/main/java/org/apache/doris/common/proc/TabletsProcDir.java	Optional “force sync tablet stats” behavior gated by session variable (cloud).
fe/fe-core/src/main/java/org/apache/doris/common/ClientPool.java	Adds a dedicated FE client pool for tablet-stats sync RPC.
fe/fe-core/src/main/java/org/apache/doris/cloud/transaction/CloudGlobalTransactionMgr.java	Threads tabletIds through commit path and marks tablets active post-commit.
fe/fe-core/src/main/java/org/apache/doris/cloud/catalog/CloudTabletRebalancer.java	Reduces memory retention by removing unused map and avoiding boxing for tabletId.
fe/fe-core/src/main/java/org/apache/doris/cloud/catalog/CloudReplica.java	Adds persisted fields for interval-ladder bookkeeping; shortens persisted keys.
fe/fe-core/src/main/java/org/apache/doris/catalog/CloudTabletStatMgr.java	Implements active/interval-ladder fetching, precomputed top-N filtering, and master-to-follower stats push.
fe/fe-core/src/main/java/org/apache/doris/alter/CloudSchemaChangeJobV2.java	Marks related tablets active after schema change completion.
fe/fe-core/src/main/java/org/apache/doris/alter/CloudRollupJobV2.java	Marks related tablets active after rollup completion.
fe/fe-common/src/main/java/org/apache/doris/common/Config.java	Adds cloud checkpoint staleness threshold + tablet stats sync/version configs.
be/src/cloud/cloud_meta_mgr.cpp	Sends tabletIds alongside commit/compaction notifications to FE.

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Category	Coverage
Function Coverage	52.85% (19677/37235)
Line Coverage	36.24% (184220/508331)
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Function Coverage	72.73% (26510/36449)
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Branch Coverage	55.43% (103251/186272)