org.apache.hadoop.hbase.regionserver.storefiletracker

Interface StoreFileTracker

All Known Implementing Classes:

DefaultStoreFileTracker, FileBasedStoreFileTracker, MigrationStoreFileTracker, StoreFileTrackerBase

@InterfaceAudience.Private
public interface StoreFileTracker

An interface to define how we track the store files for a give store.

In the old time, we will write store to a tmp directory first, and then rename it to the actual data file. And once a store file is under data directory, we will consider it as 'committed'. And we need to do listing when loading store files.

When cloud age is coming, now we want to store the store files on object storage, where rename and list are not as cheap as on HDFS, especially rename. Although introducing a metadata management layer for object storage could solve the problem, but we still want HBase to run on pure object storage, so here we introduce this interface to abstract how we track the store files. For the old implementation, we just persist nothing here, and do listing to load store files. When running on object storage, we could persist the store file list in a system region, or in a file on the object storage, to make it possible to write directly into the data directory to avoid renaming, and also avoid listing when loading store files.

The implementation requires to be thread safe as flush and compaction may occur as the same time, and we could also do multiple compactions at the same time. As the implementation may choose to persist the store file list to external storage, which could be slow, it is the duty for the callers to not call it inside a lock which may block normal read/write requests.

Method Summary

Modifier and Type	Method and Description
void	add(Collection<StoreFileInfo> newFiles) Add new store files.
StoreFileWriter	createWriter(CreateStoreFileWriterParams params) Create a writer for writing new store files.
List<StoreFileInfo>	load() Load the store files list when opening a region.
void	replace(Collection<StoreFileInfo> compactedFiles, Collection<StoreFileInfo> newFiles) Add new store files and remove compacted store files after compaction.
boolean	requireWritingToTmpDirFirst() Whether the implementation of this tracker requires you to write to temp directory first, i.e, does not allow broken store files under the actual data directory.
void	set(List<StoreFileInfo> files) Set the store files.
TableDescriptorBuilder	updateWithTrackerConfigs(TableDescriptorBuilder builder) Adds StoreFileTracker implementations specific configurations into the table descriptor.

Method Detail

load

List<StoreFileInfo> load()
                  throws IOException

Load the store files list when opening a region.

Throws:

IOException

add

void add(Collection<StoreFileInfo> newFiles)
  throws IOException

Add new store files.

Used for flush and bulk load.

Throws:

IOException

replace

void replace(Collection<StoreFileInfo> compactedFiles,
             Collection<StoreFileInfo> newFiles)
      throws IOException

Add new store files and remove compacted store files after compaction.

Throws:

IOException

set

void set(List<StoreFileInfo> files)
  throws IOException

Set the store files.

Throws:

IOException

createWriter

StoreFileWriter createWriter(CreateStoreFileWriterParams params)
                      throws IOException

Create a writer for writing new store files.

Returns:

Writer for a new StoreFile

Throws:

IOException

updateWithTrackerConfigs

TableDescriptorBuilder updateWithTrackerConfigs(TableDescriptorBuilder builder)

Adds StoreFileTracker implementations specific configurations into the table descriptor.

This is used to avoid accidentally data loss when changing the cluster level store file tracker implementation, and also possible misconfiguration between master and region servers.

See HBASE-26246 for more details.

Parameters:

builder - The table descriptor builder for the given table.

requireWritingToTmpDirFirst

boolean requireWritingToTmpDirFirst()

Whether the implementation of this tracker requires you to write to temp directory first, i.e, does not allow broken store files under the actual data directory.