org.apache.hadoop.hbase.util

Class FSTableDescriptors

java.lang.Object

org.apache.hadoop.hbase.util.FSTableDescriptors

All Implemented Interfaces:

TableDescriptors

@InterfaceAudience.Private
public class FSTableDescriptors
extends Object
implements TableDescriptors

Implementation of TableDescriptors that reads descriptors from the passed filesystem. It expects descriptors to be in a file in the TABLEINFO_DIR subdir of the table's directory in FS. Can be read-only -- i.e. does not modify the filesystem or can be read and write.

Also has utility for keeping up the table descriptors tableinfo file. The table schema file is kept in the TABLEINFO_DIR subdir of the table directory in the filesystem. It has a TABLEINFO_FILE_PREFIX and then a suffix that is the edit sequenceid: e.g. .tableinfo.0000000003. This sequenceid is always increasing. It starts at zero. The table schema file with the highest sequenceid has the most recent schema edit. Usually there is one file only, the most recent but there may be short periods where there are more than one file. Old files are eventually cleaned. Presumption is that there will not be lots of concurrent clients making table schema edits. If so, the below needs a bit of a reworking and perhaps some supporting api in hdfs.

Constructor Summary

Constructors

Constructor and Description
FSTableDescriptors(org.apache.hadoop.conf.Configuration conf) Construct a FSTableDescriptors instance using the hbase root dir of the given conf and the filesystem where that root dir lives.
FSTableDescriptors(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path rootdir)
FSTableDescriptors(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path rootdir, boolean fsreadonly, boolean usecache)

Method Summary

Modifier and Type	Method and Description
static TableDescriptorBuilder	createMetaTableDescriptorBuilder(org.apache.hadoop.conf.Configuration conf)
boolean	createTableDescriptor(TableDescriptor htd) Create new TableDescriptor in HDFS.
boolean	createTableDescriptor(TableDescriptor htd, boolean forceCreation) Create new TableDescriptor in HDFS.
static boolean	createTableDescriptorForTableDirectory(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path tableDir, TableDescriptor htd, boolean forceCreation) Create a new TableDescriptor in HDFS in the specified table directory.
boolean	createTableDescriptorForTableDirectory(org.apache.hadoop.fs.Path tableDir, TableDescriptor htd, boolean forceCreation) Create a new TableDescriptor in HDFS in the specified table directory.
TableDescriptor	get(TableName tableName) Get the current table descriptor for the given table, or null if none exists.
Map<String,TableDescriptor>	getAll() Returns a map from table name to table descriptor for all tables.
Map<String,TableDescriptor>	getByNamespace(String name) Find descriptors by namespace.
static TableDescriptor	getTableDescriptorFromFs(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path tableDir) Returns the latest table descriptor for the table located at the given directory directly from the file system if it exists.
static TableDescriptor	getTableDescriptorFromFs(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path hbaseRootDir, TableName tableName) Returns the latest table descriptor for the given table directly from the file system if it exists, bypassing the local cache.
static org.apache.hadoop.fs.FileStatus	getTableInfoPath(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path tableDir) Find the most current table info file for the table located in the given table directory.
protected boolean	isUsecache()
TableDescriptor	remove(TableName tablename) Removes the table descriptor from the local cache and returns it.
static TableDescriptor	tryUpdateAndGetMetaTableDescriptor(org.apache.hadoop.conf.Configuration conf, org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path rootdir)
static void	tryUpdateMetaTableDescriptor(org.apache.hadoop.conf.Configuration conf)
void	update(TableDescriptor td, boolean cacheOnly) Add or update descriptor

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hadoop.hbase.TableDescriptors

exists, update

Constructor Detail

FSTableDescriptors

public FSTableDescriptors(org.apache.hadoop.conf.Configuration conf)
                   throws IOException

Construct a FSTableDescriptors instance using the hbase root dir of the given conf and the filesystem where that root dir lives. This instance can do write operations (is not read only).

Throws:

IOException

FSTableDescriptors

public FSTableDescriptors(org.apache.hadoop.fs.FileSystem fs,
                          org.apache.hadoop.fs.Path rootdir)

FSTableDescriptors

public FSTableDescriptors(org.apache.hadoop.fs.FileSystem fs,
                          org.apache.hadoop.fs.Path rootdir,
                          boolean fsreadonly,
                          boolean usecache)

Method Detail

tryUpdateMetaTableDescriptor

public static void tryUpdateMetaTableDescriptor(org.apache.hadoop.conf.Configuration conf)
                                         throws IOException

Throws:

IOException

tryUpdateAndGetMetaTableDescriptor

public static TableDescriptor tryUpdateAndGetMetaTableDescriptor(org.apache.hadoop.conf.Configuration conf,
                                                                 org.apache.hadoop.fs.FileSystem fs,
                                                                 org.apache.hadoop.fs.Path rootdir)
                                                          throws IOException

Throws:

IOException

createMetaTableDescriptorBuilder

public static TableDescriptorBuilder createMetaTableDescriptorBuilder(org.apache.hadoop.conf.Configuration conf)
                                                               throws IOException

Throws:

IOException

isUsecache

protected boolean isUsecache()

get

@Nullable
public TableDescriptor get(TableName tableName)

Get the current table descriptor for the given table, or null if none exists.

Uses a local cache of the descriptor but still checks the filesystem on each call if fsvisited is not true, i.e, we haven't done a full scan yet, to see if a newer file has been created since the cached one was read.

Specified by:

get in interface TableDescriptors

Returns:

TableDescriptor for tablename

getAll

public Map<String,TableDescriptor> getAll()
                                   throws IOException

Returns a map from table name to table descriptor for all tables.

Specified by:

getAll in interface TableDescriptors

Returns:

Map of all descriptors.

Throws:

IOException

getByNamespace

public Map<String,TableDescriptor> getByNamespace(String name)
                                           throws IOException

Find descriptors by namespace.

Specified by:

getByNamespace in interface TableDescriptors

Returns:

Map of all descriptors.

Throws:

IOException

See Also:

get(org.apache.hadoop.hbase.TableName)

update

public void update(TableDescriptor td,
                   boolean cacheOnly)
            throws IOException

Description copied from interface: TableDescriptors

Add or update descriptor

Specified by:

update in interface TableDescriptors

Parameters:

td - Descriptor to set into TableDescriptors

cacheOnly - only add the given htd to cache, without updating the storage. For example, when creating table, we will write the descriptor to fs when creating the fs layout, so we do not need to update the fs again.

Throws:

IOException

remove

public TableDescriptor remove(TableName tablename)
                       throws IOException

Removes the table descriptor from the local cache and returns it. If not in read only mode, it also deletes the entire table directory(!) from the FileSystem.

Specified by:

remove in interface TableDescriptors

Returns:

Instance of table descriptor or null if none found.

Throws:

IOException

getTableInfoPath

public static org.apache.hadoop.fs.FileStatus getTableInfoPath(org.apache.hadoop.fs.FileSystem fs,
                                                               org.apache.hadoop.fs.Path tableDir)
                                                        throws IOException

Find the most current table info file for the table located in the given table directory. Looks within the TABLEINFO_DIR subdirectory of the given directory for any table info files and takes the 'current' one - meaning the one with the highest sequence number if present or no sequence number at all if none exist (for backward compatibility from before there were sequence numbers).

Returns:

The file status of the current table info file or null if it does not exist

Throws:

IOException

getTableDescriptorFromFs

public static TableDescriptor getTableDescriptorFromFs(org.apache.hadoop.fs.FileSystem fs,
                                                       org.apache.hadoop.fs.Path hbaseRootDir,
                                                       TableName tableName)
                                                throws IOException

Returns the latest table descriptor for the given table directly from the file system if it exists, bypassing the local cache. Returns null if it's not found.

Throws:

IOException

getTableDescriptorFromFs

public static TableDescriptor getTableDescriptorFromFs(org.apache.hadoop.fs.FileSystem fs,
                                                       org.apache.hadoop.fs.Path tableDir)
                                                throws IOException

Returns the latest table descriptor for the table located at the given directory directly from the file system if it exists.

Throws:

TableInfoMissingException - if there is no descriptor

IOException

createTableDescriptor

public boolean createTableDescriptor(TableDescriptor htd)
                              throws IOException

Create new TableDescriptor in HDFS. Happens when we are creating table. Used by tests.

Returns:

True if we successfully created file.

Throws:

IOException

createTableDescriptor

public boolean createTableDescriptor(TableDescriptor htd,
                                     boolean forceCreation)
                              throws IOException

Create new TableDescriptor in HDFS. Happens when we are creating table. If forceCreation is true then even if previous table descriptor is present it will be overwritten

Returns:

True if we successfully created file.

Throws:

IOException

createTableDescriptorForTableDirectory

public boolean createTableDescriptorForTableDirectory(org.apache.hadoop.fs.Path tableDir,
                                                      TableDescriptor htd,
                                                      boolean forceCreation)
                                               throws IOException

Create a new TableDescriptor in HDFS in the specified table directory. Happens when we create a new table during cluster start or in Clone and Create Table Procedures. Checks readOnly flag passed on construction.

Parameters:

tableDir - table directory under which we should write the file

htd - description of the table to write

forceCreation - if true,then even if previous table descriptor is present it will be overwritten

Returns:

true if the we successfully created the file, false if the file already exists and we weren't forcing the descriptor creation.

Throws:

IOException - if a filesystem error occurs

createTableDescriptorForTableDirectory

public static boolean createTableDescriptorForTableDirectory(org.apache.hadoop.fs.FileSystem fs,
                                                             org.apache.hadoop.fs.Path tableDir,
                                                             TableDescriptor htd,
                                                             boolean forceCreation)
                                                      throws IOException

Create a new TableDescriptor in HDFS in the specified table directory. Happens when we create a new table snapshoting. Does not enforce read-only. That is for caller to determine.

Parameters:

fs - Filesystem to use.

tableDir - table directory under which we should write the file

htd - description of the table to write

forceCreation - if true,then even if previous table descriptor is present it will be overwritten

Returns:

true if the we successfully created the file, false if the file already exists and we weren't forcing the descriptor creation.

Throws:

IOException - if a filesystem error occurs