Package org.apache.druid.metadata

Interface SegmentsMetadataManager

All Known Implementing Classes:
SqlSegmentsMetadataManager, SqlSegmentsMetadataManagerV2
public interface SegmentsMetadataManager
Polls the metadata store periodically and builds a timeline of used segments (and schemas if schema caching on the Coordinator is enabled).

This class is provisioned by SegmentsMetadataManagerProvider and must be bound on the Coordinator/Overlord accordingly.

  • Method Details

    • start

      void start()
      Initializes the manager when the service is being started.

    • stop

      void stop()
      Cleans up resources when the service is being shut down.

    • startPollingDatabasePeriodically

      void startPollingDatabasePeriodically()
      Starts polling segments from the metadata store upon becoming leader.

    • stopPollingDatabasePeriodically

      void stopPollingDatabasePeriodically()
      Stops polling segments from the metadata store when leadership is lost.

    • isPollingDatabasePeriodically

      boolean isPollingDatabasePeriodically()
      Returns:
      true if currently the leader and polling the metadata store.

    • getRecentDataSourcesSnapshot

      DataSourcesSnapshot getRecentDataSourcesSnapshot()
      Returns the latest snapshot containing all used segments currently cached on the manager. This method returns immediately if the poll period has not elapsed since the latest snapshot was built. Otherwise, it blocks until the snapshot has been refreshed.

    • forceUpdateDataSourcesSnapshot

      DataSourcesSnapshot forceUpdateDataSourcesSnapshot()
      Forces the manager to poll the metadata store and update its snapshot. If a poll is already in progress, a new poll is not started. This method blocks until the poll finishes and the snapshot has been refreshed.
      Returns:
      The updated snapshot.

    • populateUsedFlagLastUpdatedAsync

      void populateUsedFlagLastUpdatedAsync()
      Populates used_status_last_updated column in the segments table iteratively until there are no segments with a NULL value for that column.

    • stopAsyncUsedFlagLastUpdatedUpdate

      void stopAsyncUsedFlagLastUpdatedUpdate()