[CELEBORN-2316] Introduce metadata operation metrics

[AmandeepSingh285]

What changes were proposed in this pull request?

Adding metrics around rocks DB operations. Metrics to have success and failure count for metadata operations for rocksDB observability.

Why are the changes needed?

Adding metrics around metadata operations. Current implementation, metadata operations do not have any observability added. RocksDB goes into a read only mode when any critical errors are encountered which results in all write operations failing.
Observability around metadata operations is critical and failures could result in metadata entering an inconsistent state.

Does this PR resolve a correctness bug?

No

Does this PR introduce any user-facing change?

No

How was this patch tested?

Tested in local staging setup -

[SteNicholas]

@AmandeepSingh285, thanks for first contribution. Please run dev/reformat to format code changes. Then add introduced metrics into celeborn-dashboard.json.

[Copilot]

Pull request overview

This PR adds worker-side metrics to improve observability of RocksDB-backed metadata operations by counting read/write successes and failures.

Changes:

• Introduces MetadataMetrics and wires it into RocksDB put/get/delete and iterator reads/seeks to track success/failure counts.
• Registers a new labeled counter in WorkerSource for metadata operation status (operation = read/write, status = success/fail).
• Threads WorkerSource / AbstractSource through DBProvider.initDB(...) call sites so RocksDB can emit metrics.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
worker/src/test/java/org/apache/celeborn/service/deploy/worker/shuffledb/DBProviderSuiteJ.java	Updates DB init calls to pass a WorkerSource after initDB signature change.
worker/src/main/scala/org/apache/celeborn/service/deploy/worker/storage/StorageManager.scala	Passes workerSource into DB initialization for graceful-shutdown recovery DB.
worker/src/main/scala/org/apache/celeborn/service/deploy/worker/WorkerSource.scala	Adds labeled counters for metadata read/write success/failure.
worker/src/main/java/org/apache/celeborn/service/deploy/worker/storage/PartitionFilesSorter.java	Passes source into DB initialization for sorted-files recovery DB.
worker/src/main/java/org/apache/celeborn/service/deploy/worker/shuffledb/RocksDBIterator.java	Wraps iterator seek/next in metric-recording reads (including status() checks).
worker/src/main/java/org/apache/celeborn/service/deploy/worker/shuffledb/RocksDB.java	Wraps RocksDB put/get/delete with metric recording and passes metrics into iterator.
worker/src/main/java/org/apache/celeborn/service/deploy/worker/shuffledb/MetadataMetrics.java	New helper to record labeled success/failure counters around RocksDB operations.
worker/src/main/java/org/apache/celeborn/service/deploy/worker/shuffledb/DBProvider.java	Extends initDB to accept an AbstractSource and constructs RocksDB with it.

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[AmandeepSingh285]

@SteNicholas will work on updating the celeborn dashboard. Could you help with an initial review for the change. Thanks!