Package com.linkedin.venice.cleaner

Class BackupVersionOptimizationService

java.lang.Object

com.linkedin.venice.service.AbstractVeniceService

com.linkedin.venice.cleaner.BackupVersionOptimizationService

All Implemented Interfaces:

ResourceReadUsageTracker, Closeable, AutoCloseable

public class BackupVersionOptimizationService
extends AbstractVeniceService
implements ResourceReadUsageTracker

This class is used to periodically scan inactive store versions and perform optimization if the inactive period of some store version meets the pre-configured threshold, this class will trigger the database reopen action to unload unnecessary RAM usage, which was built up when there were active reads coming. The optimization follows the following rules: 1. Don't touch current version no matter whether it is being actively used in the read path or not. 2. Don't touch versions, which are not ready-to-serve yet. 3. If some specific store version is ready-to-serve, but haven't been active recently, this class will reopen all the storage partitions belonging to the inactive version to free up unnecessary RAM usage. 4. Don't reopen the database again if there is no more read usage after the optimization. This optimization is mainly for RocksDBStorageEngine. 1. Block-based format. Reopening the database will release the index/filter usages from the shared block cache. 2. Plain-table format. Reopening the database will un-mmap the file contents, which were brought into memory by the past read requests.

Nested Class Summary

Nested classes/interfaces inherited from class com.linkedin.venice.service.AbstractVeniceService

AbstractVeniceService.ServiceState

Field Summary

Fields inherited from class com.linkedin.venice.service.AbstractVeniceService

logger, serviceState

Constructor Summary

Constructors

Constructor	Description
BackupVersionOptimizationService(ReadOnlyStoreRepository storeRepository, StorageEngineRepository storageEngineRepository, long noReadThresholdMSForDatabaseOptimization, long scheduleIntervalSeconds, BackupVersionOptimizationServiceStats stats)	Allocate and initialize a new BackupVersionOptimizationService object.

Method Summary

Modifier and Type	Method	Description
void	recordReadUsage(String resourceName)
boolean	startInner()
void	stopInner()

Methods inherited from class com.linkedin.venice.service.AbstractVeniceService

close, getName, isRunning, start, stop

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

BackupVersionOptimizationService

public BackupVersionOptimizationService(ReadOnlyStoreRepository storeRepository,
 StorageEngineRepository storageEngineRepository,
 long noReadThresholdMSForDatabaseOptimization,
 long scheduleIntervalSeconds,
 BackupVersionOptimizationServiceStats stats)

Allocate and initialize a new BackupVersionOptimizationService object.

Parameters:

storeRepository - provides readonly operations to access stores.

storageEngineRepository - local storage engines for a server node.

noReadThresholdMSForDatabaseOptimization - controls the no read threshold for database optimization to kick in.

scheduleIntervalSeconds - sets the scheduling interval for this service.

stats - records the statistics for this service.

Method Details

startInner

public boolean startInner()
                   throws Exception

Specified by:

startInner in class AbstractVeniceService

Returns:

true if the service is completely started, false if it is still starting asynchronously (in this case, it is the implementer's responsibility to set AbstractVeniceService.serviceState to AbstractVeniceService.ServiceState.STARTED upon completion of the async work).

Throws:

Exception

stopInner

public void stopInner()
               throws Exception

Specified by:

stopInner in class AbstractVeniceService

Throws:

Exception

recordReadUsage

public void recordReadUsage(String resourceName)

Specified by:

recordReadUsage in interface ResourceReadUsageTracker