HIVE-29423: Move delete_column_statistics_req out from HMSHandler

[rtrivedi12]

What changes were proposed in this pull request?

Extract delete_column_statistics_req logic from HMSHandler into a new DeleteColumnStatisticsHandler, following the existing @RequestHandler / AbstractRequestHandler

• Add DeleteColumnStatisticsHandler for table- and partition-level column statistics deletion, including transactional listener events and post-commit notification.
• HMSHandler.delete_column_statistics_req() used to audit logging (startFunction / endFunction) and delegation via AbstractRequestHandler.offer(this, req).

Why are the changes needed?

HMSHandler is being decomposed into focused request handlers (HIVE-27224).

Does this PR introduce any user-facing change?

No

How was this patch tested?

mvn test -pl standalone-metastore/metastore-server -am
-Dtest=TestStats,TestStatisticsManagement

[Copilot]

Pull request overview

This PR continues the metastore handler decomposition by extracting the delete_column_statistics_req implementation out of HMSHandler into a dedicated DeleteColumnStatisticsHandler based on the existing @RequestHandler / AbstractRequestHandler framework.

Changes:

• Refactors HMSHandler.delete_column_statistics_req() to delegate execution to AbstractRequestHandler.offer(this, req) while preserving audit start/end behavior and standard exception translation.
• Adds DeleteColumnStatisticsHandler to implement table- and partition-level column statistics deletion, including transactional listener notifications and post-commit event publication.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/HMSHandler.java	Delegates delete_column_statistics_req to the request-handler framework and routes exceptions through standard handling while ensuring endFunction receives any thrown exception.
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/handler/DeleteColumnStatisticsHandler.java	New request handler implementing the delete column statistics logic formerly in HMSHandler, including transaction and listener event logic.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/handler/DeleteColumnStatisticsHandler.java:154

• Post-commit listener notification is using the transactional listener list. Transactional listeners are already notified during execution; after commit this should notify the regular listeners (handler.getListeners()). As written, non-transactional listeners will never receive DELETE_*_COLUMN_STAT events and transactional listeners may receive duplicate notifications.

  protected void afterExecute(DeleteColumnStatisticsResult result) throws TException, IOException {
    if (result != null && !handler.getListeners().isEmpty()) {
      for (ListenerEvent event : result.events()) {
        MetaStoreListenerNotifier.notifyEvent(handler.getTransactionalListeners(), result.eventType(), event);
      }
    }

[sonarqubecloud]

Quality Gate passed

Issues
6 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.8% Duplication on New Code

See analysis details on SonarQube Cloud