Master server. More...

Collaboration diagram for Master:

Namespaces
	Hypertable::OperationState
	Master operation states.

	Hypertable::Dependency
	Master dependency strings

	Hypertable::TableMaintenance
	Table maintenance constants

Classes
class	Hypertable::BalancePlanAuthority
	Central authority for balance plans. More...

struct	Hypertable::BalancePlanAuthority::RecoveryPlans
	Holds plans for each range type. More...

struct	Hypertable::BalancePlanAuthority::lt_move_spec
	StrictWeakOrdering class for set of RangeMoveSpecs. More...

class	Hypertable::ConnectionHandler
	Handles incoming Master requests. More...

class	Hypertable::Context
	Execution context for the Master. More...

class	Hypertable::Context::RecoveryState

class	Hypertable::DispatchHandlerOperation
	DispatchHandler class for managing async RangeServer requests. More...

class	Hypertable::DispatchHandlerOperation::Result
	Holds request result information. More...

struct	Hypertable::DispatchHandlerOperation::LtEventPtr
	Strict Weak Ordering for comparing events by source address. More...

class	Hypertable::DispatchHandlerOperationCompact
	Dispatch handler to aggregate a set of RangeServer::compact results. More...

class	Hypertable::DispatchHandlerOperationSetState
	DispatchHandler class for gathering responses to a set of RangeServer::set_state() requests. More...

class	Hypertable::DispatchHandlerOperationSystemStatus
	Carries out scatter/gather requests for RangeServer status. More...

class	Hypertable::DispatchHandlerOperationToggleTableMaintenance
	Dispatch handler for either enabling or disabling table maintenance by issuing requests to range servers and aggregating the responses. More...

class	Hypertable::Master::HyperspaceMasterFile
	Facilitates operations on the master file in Hyperspace. More...

class	Hypertable::MetricsHandler
	Collects and publishes Master metrics. More...

class	Hypertable::NotificationMessage
	Holds a notification message to be deliverd to the administrator. More...

class	Hypertable::Operation
	Abstract base class for master operations. More...

class	Hypertable::OperationAlterTable
	Carries out an alter table operation. More...

class	Hypertable::OperationCompact
	Carries out a manual compaction operation. More...

class	Hypertable::OperationCreateTable
	Carries out a create table operation. More...

class	Hypertable::OperationDropTable
	Carries out a drop table operation. More...

class	Hypertable::OperationEphemeral
	Abstract base class for ephemeral operations. More...

class	Hypertable::OperationGatherStatistics
	Gathers and processes RangeServer statistics. More...

class	Hypertable::OperationProcessor
	Runs a set of operaions with dependency relationships. More...

struct	Hypertable::OperationProcessor::operation_t

struct	Hypertable::OperationProcessor::execution_time_t

struct	Hypertable::OperationProcessor::label_t

struct	Hypertable::OperationProcessor::busy_t

struct	Hypertable::OperationProcessor::permanent_t

struct	Hypertable::OperationProcessor::vertex_info

class	Hypertable::OperationProcessor::OperationVertex

class	Hypertable::OperationProcessor::ThreadContext

struct	Hypertable::OperationProcessor::not_permanent

struct	Hypertable::OperationProcessor::ltvertexinfo

class	Hypertable::OperationProcessor::Worker

class	Hypertable::OperationRecover
	Carries out recovery operaton for a range server. More...

class	Hypertable::OperationRecreateIndexTables
	Reconstructs a table's index tables. More...

class	Hypertable::OperationRegisterServerBlocker
	Blocks range server registration. More...

class	Hypertable::OperationSetState
	Carries out a set variables operation. More...

class	Hypertable::OperationToggleTableMaintenance
	Enables or disables maintenance for a table. More...

class	Hypertable::RangeServerHyperspaceCallback
	Callback class for range server lock files. More...

class	Hypertable::RecoveredServers
	Set of recovered servers. More...

class	Hypertable::ReferenceManager
	Holds references to operations that are to be manually removed. More...

class	Hypertable::ResponseManagerContext
	Implementation shared by ResponseManager objects. More...

class	Hypertable::ResponseManagerContext::OperationRec
	Record holding completed operation information. More...

class	Hypertable::ResponseManagerContext::DeliveryRec
	Record holding response delivery information for an operation. More...

class	Hypertable::ResponseManager
	Manages the sending of operation results back to clients. More...

class	Hypertable::SystemState
	Holds persistent global system state. More...

Typedefs
typedef std::shared_ptr < BalancePlanAuthority >	Hypertable::BalancePlanAuthorityPtr
	Smart pointer to BalancePlanAuthority. More...

typedef std::shared_ptr< Context >	Hypertable::ContextPtr
	Smart pointer to Context. More...

typedef std::shared_ptr < DispatchHandlerOperation >	Hypertable::DispatchHandlerOperationPtr
	Smart pointer to DispatchHandlerOperation. More...

typedef std::shared_ptr < DispatchHandlerOperationCompact >	Hypertable::DispatchHandlerOperationCompactPtr
	Smart pointer to DispatchHandlerOperationCompact. More...

typedef std::shared_ptr < DispatchHandlerOperationSetState >	Hypertable::DispatchHandlerOperationSetStatePtr
	Smart pointer to DispatchHandlerOperationSetState. More...

typedef std::shared_ptr < DispatchHandlerOperationSystemStatus >	Hypertable::DispatchHandlerOperationSystemStatusPtr
	Smart pointer to DispatchHandlerOperationSystemStatus. More...

typedef std::shared_ptr < MetricsHandler >	Hypertable::MetricsHandlerPtr
	Smart pointer to MetricsHandler. More...

typedef std::set< String >	Hypertable::DependencySet
	Set of dependency string. More...

typedef std::shared_ptr < Operation >	Hypertable::OperationPtr
	Smart pointer to Operation. More...

typedef std::shared_ptr < RecoveredServers >	Hypertable::RecoveredServersPtr
	Smart pointer to RecoveredServers. More...

typedef std::shared_ptr < SystemState >	Hypertable::SystemStatePtr
	Shared smart pointer to SystemState. More...

Enumerations
enum	{ Hypertable::OperationState::INITIAL = 0, Hypertable::OperationState::COMPLETE = 1, Hypertable::OperationState::UNUSED = 2, Hypertable::OperationState::STARTED = 3, Hypertable::OperationState::ASSIGN_ID = 4, Hypertable::OperationState::ASSIGN_LOCATION = 5, Hypertable::OperationState::ASSIGN_METADATA_RANGES = 6, Hypertable::OperationState::LOAD_RANGE = 7, Hypertable::OperationState::LOAD_ROOT_METADATA_RANGE = 8, Hypertable::OperationState::LOAD_SECOND_METADATA_RANGE = 9, Hypertable::OperationState::WRITE_METADATA = 10, Hypertable::OperationState::CREATE_RS_METRICS = 11, Hypertable::OperationState::VALIDATE_SCHEMA = 12, Hypertable::OperationState::SCAN_METADATA = 13, Hypertable::OperationState::ISSUE_REQUESTS = 14, Hypertable::OperationState::UPDATE_HYPERSPACE = 15, Hypertable::OperationState::ACKNOWLEDGE = 16, Hypertable::OperationState::FINALIZE = 17, Hypertable::OperationState::CREATE_INDEX = 18, Hypertable::OperationState::CREATE_QUALIFIER_INDEX = 19, Hypertable::OperationState::PREPARE = 20, Hypertable::OperationState::COMMIT = 21, Hypertable::OperationState::PHANTOM_LOAD = 22, Hypertable::OperationState::REPLAY_FRAGMENTS = 23, Hypertable::OperationState::CREATE_INDICES = 24, Hypertable::OperationState::DROP_INDICES = 25, Hypertable::OperationState::SUSPEND_TABLE_MAINTENANCE = 26, Hypertable::OperationState::RESUME_TABLE_MAINTENANCE = 27, Hypertable::OperationState::DROP_VALUE_INDEX = 28, Hypertable::OperationState::DROP_QUALIFIER_INDEX = 29, Hypertable::OperationState::RENAME_VALUE_INDEX = 30, Hypertable::OperationState::RENAME_QUALIFIER_INDEX = 31 }
	Enumeration for operation states. More...

enum	{ Hypertable::OperationRecover::RESTART = 1 }

Functions
	Hypertable::DispatchHandlerOperationSystemStatus::Result::Result (const std::string &location, InetAddr addr)

	Hypertable::DispatchHandlerOperationSystemStatus::DispatchHandlerOperationSystemStatus (ContextPtr &context, Timer &timer)
	Constructor. More...

void	Hypertable::DispatchHandlerOperationSystemStatus::initialize (std::vector< Result > &results)
	Performs initialization. More...

void	Hypertable::DispatchHandlerOperationSystemStatus::start (const String &location) override
	Issues a status request for the range server at `location`. More...

void	Hypertable::DispatchHandlerOperationSystemStatus::result_callback (const EventPtr &event) override
	Handles a status request event. More...

int	main (int argc, char **argv)

void	Hypertable::Utility::get_table_server_set (ContextPtr &context, const String &id, const String &row, StringSet &servers)
	Gets set of servers holding ranges for a given table. More...

bool	Hypertable::Utility::table_exists (ContextPtr &context, const String &name, String &id)
	Checks if table exists and returns table ID. More...

bool	Hypertable::Utility::table_exists (ContextPtr &context, const String &id)
	Checks if table ID exists. More...

TableParts	Hypertable::Utility::get_index_parts (const std::string &schema)
	Gets index parts specified in schema. More...

void	Hypertable::Utility::verify_table_name_availability (ContextPtr &context, const String &name, String &id)
	Checks if table name is available. More...

void	Hypertable::Utility::create_table_in_hyperspace (ContextPtr &context, const String &name, const String &schema_str, TableIdentifierManaged *table)
	Creates a table in Hyperspace. More...

void	Hypertable::Utility::prepare_index (ContextPtr &context, const String &name, const String &schema_str, bool qualifier, String &index_name, String &index_schema)
	Prepares index schema and table name. More...

void	Hypertable::Utility::create_table_write_metadata (ContextPtr &context, TableIdentifier *table)
	Creates initial METADATA table entry for `table`. More...

bool	Hypertable::Utility::next_available_server (ContextPtr &context, String &location, bool urgent=false)
	Gets name of next available server. More...

void	Hypertable::Utility::create_table_load_range (ContextPtr &context, const String &location, TableIdentifier &table, RangeSpec &range, bool needs_compaction)
	Loads a table's initial range. More...

void	Hypertable::Utility::create_table_acknowledge_range (ContextPtr &context, const String &location, TableIdentifier &table, RangeSpec &range)
	Calls RangeServer::acknowledge_load for a range. More...

int64_t	Hypertable::Utility::range_hash_code (const TableIdentifier &table, const RangeSpec &range, const String &qualifier)
	Returns a hash code for a range with an optional qualifer string. More...

String	Hypertable::Utility::range_hash_string (const TableIdentifier &table, const RangeSpec &range, const String &qualifier)
	Returns string representation of hash code for a range with an optional qualifer string. More...

String	Hypertable::Utility::root_range_location (ContextPtr &context)
	Returns location of root METADATA range. More...

bool	Hypertable::Utility::status (ContextPtr &context, Timer &timer, Status &status)
	Runs a status check on the master. More...

void	Hypertable::Utility::shutdown_rangeserver (ContextPtr &context, CommAddress &addr)
	Sends a shutdown command to a rangeserver. More...

Variables
std::string	Hypertable::DispatchHandlerOperationSystemStatus::Result::location

InetAddr	Hypertable::DispatchHandlerOperationSystemStatus::Result::addr

int32_t	Hypertable::DispatchHandlerOperationSystemStatus::Result::error {Error::NO_RESPONSE}

std::string	Hypertable::DispatchHandlerOperationSystemStatus::Result::message

Status	Hypertable::DispatchHandlerOperationSystemStatus::Result::status

Timer	Hypertable::DispatchHandlerOperationSystemStatus::m_timer
	Deadline timer. More...

SockAddrMap< Result * >	Hypertable::DispatchHandlerOperationSystemStatus::m_index
	Result map. More...

Detailed Description

Master server.

The Master module contains all of the definitions that make up the Master server process which is responsible for handling meta operations such the following

Creating, altering, and dropping tables
CellStore garbage collection
Orchestration of RangeServer failover
Load balancing

Typedef Documentation

typedef std::shared_ptr<BalancePlanAuthority> Hypertable::BalancePlanAuthorityPtr

Smart pointer to BalancePlanAuthority.

Definition at line 399 of file BalancePlanAuthority.h.

typedef std::shared_ptr< Context > Hypertable::ContextPtr

Smart pointer to Context.

Definition at line 265 of file Context.h.

typedef std::set<String> Hypertable::DependencySet

Set of dependency string.

Definition at line 107 of file Operation.h.

typedef std::shared_ptr<DispatchHandlerOperationCompact> Hypertable::DispatchHandlerOperationCompactPtr

Smart pointer to DispatchHandlerOperationCompact.

Definition at line 84 of file DispatchHandlerOperationCompact.h.

typedef std::shared_ptr<DispatchHandlerOperation> Hypertable::DispatchHandlerOperationPtr

Smart pointer to DispatchHandlerOperation.

Definition at line 179 of file DispatchHandlerOperation.h.

typedef std::shared_ptr<DispatchHandlerOperationSetState> Hypertable::DispatchHandlerOperationSetStatePtr

Smart pointer to DispatchHandlerOperationSetState.

Definition at line 84 of file DispatchHandlerOperationSetState.h.

typedef std::shared_ptr<DispatchHandlerOperationSystemStatus> Hypertable::DispatchHandlerOperationSystemStatusPtr

Smart pointer to DispatchHandlerOperationSystemStatus.

Definition at line 94 of file DispatchHandlerOperationSystemStatus.h.

typedef std::shared_ptr< MetricsHandler > Hypertable::MetricsHandlerPtr

Smart pointer to MetricsHandler.

Shared smart pointer to MetricsHandler.

Definition at line 107 of file MetricsHandler.h.

typedef std::shared_ptr<Operation> Hypertable::OperationPtr

Smart pointer to Operation.

Definition at line 609 of file Operation.h.

typedef std::shared_ptr<RecoveredServers> Hypertable::RecoveredServersPtr

Smart pointer to RecoveredServers.

Definition at line 112 of file RecoveredServers.h.

typedef std::shared_ptr<SystemState> Hypertable::SystemStatePtr

Shared smart pointer to SystemState.

Definition at line 191 of file SystemState.h.

Enumeration Type Documentation

anonymous enum

Enumeration for operation states.

Enumerator
INITIAL
COMPLETE
UNUSED
STARTED
ASSIGN_ID
ASSIGN_LOCATION
ASSIGN_METADATA_RANGES
LOAD_RANGE
LOAD_ROOT_METADATA_RANGE
LOAD_SECOND_METADATA_RANGE
WRITE_METADATA
CREATE_RS_METRICS
VALIDATE_SCHEMA
SCAN_METADATA
ISSUE_REQUESTS
UPDATE_HYPERSPACE
ACKNOWLEDGE
FINALIZE
CREATE_INDEX
CREATE_QUALIFIER_INDEX
PREPARE
COMMIT
PHANTOM_LOAD
REPLAY_FRAGMENTS
CREATE_INDICES
DROP_INDICES
SUSPEND_TABLE_MAINTENANCE
RESUME_TABLE_MAINTENANCE
DROP_VALUE_INDEX
DROP_QUALIFIER_INDEX
RENAME_VALUE_INDEX
RENAME_QUALIFIER_INDEX

Definition at line 53 of file Operation.h.

anonymous enum

Enumerator
RESTART

Definition at line 47 of file OperationRecover.h.

Function Documentation

void Hypertable::Utility::create_table_acknowledge_range	(	ContextPtr &	context,
		const String &	location,
		TableIdentifier &	table,
		RangeSpec &	range
	)

Calls RangeServer::acknowledge_load for a range.

Calls RangeServer::acknowledge_load for the range specified by table and range.

Parameters

context	Master context
location	RangeServer at which to call acknowledge_load
table	Table identifier
range	Range spec

Exceptions

Exception holding error code if not Error::OK, Error::TABLE_NOT_FOUND, or Error::RANGESERVER_RANGE_NOT_FOUND

Definition at line 350 of file Utility.cc.

void Hypertable::Utility::create_table_in_hyperspace	(	ContextPtr &	context,
		const String &	name,
		const String &	schema_str,
		TableIdentifierManaged *	table
	)

Creates a table in Hyperspace.

Adds a table ID mapping for name, creates a schema object from schema_str and assigns column family IDs and writes schema attribute of ID file in Hyperspace, and sets the table ID and generation attributes of table. This method also creates access group directories (/hypertable/tables/$TABLE_ID/$ACCESS_GROUP) for the table in the DFS.

Parameters

context	Master context
name	Table name to create
schema_str	Schema XML string
table	Pointer to table identifier

Definition at line 182 of file Utility.cc.

void Hypertable::Utility::create_table_load_range	(	ContextPtr &	context,
		const String &	location,
		TableIdentifier &	table,
		RangeSpec &	range,
		bool	needs_compaction
	)

Loads a table's initial range.

Load's a table's initial range in the server specified by location. A RangeState object is initialized with the split size and passed into the RangeServer::load_range call. The split size is set as follows:

If table is metadata, split size is set to the value of the Hypertable.RangeServer.Range.MetadataSplitSize property if it is set, otherwise it is set to the value of the Hypertable.RangeServer.Range.SplitSize property.
If table is not metadata, split size is set to the value of the Hypertable.RangeServer.Range.SplitSize property if Hypertable.Master.Split.SoftLimitEnabled is false. Otherwise, if Hypertable.Master.Split.SoftLimitEnabled is true, the split size is set to Hypertable.RangeServer.Range.SplitSize / min(64, server_count*2)

Parameters

context	Master context
location	RangeServer in which to load initial range
table	Table identifier
range	Range spec
needs_compaction	Needs compaction flag

Definition at line 313 of file Utility.cc.

void Hypertable::Utility::create_table_write_metadata	(	ContextPtr &	context,
		TableIdentifier *	table
	)

Creates initial METADATA table entry for table.

Creates the initial METADATA table entry for table by writing a new StartRow column with row key formulated as table_id + ":" + Key::END_ROW_MARKER. The value is set to NULL unless table is METADATA in which case it is set to Key::END_ROOT_ROW.

Parameters

context	Master context
table	Table identifier for which to create initial METADATA entry

Definition at line 275 of file Utility.cc.

DispatchHandlerOperationSystemStatus::DispatchHandlerOperationSystemStatus	(	ContextPtr &	context,
		Timer &	timer
	)

Constructor.

Parameters

context	Master context
timer	Deadline timer

Definition at line 33 of file DispatchHandlerOperationSystemStatus.cc.

TableParts Hypertable::Utility::get_index_parts ( const std::string & schema )

Gets index parts specified in schema.

Returns a TableParts object specifying the indices that are specified in schema.

Parameters

schema Schema for which to obtain index parts

Returns: TableParts object specifying indices specified in schema

Definition at line 124 of file Utility.cc.

void Hypertable::Utility::get_table_server_set	(	ContextPtr &	context,
		const String &	id,
		const String &	row,
		StringSet &	servers
	)

Gets set of servers holding ranges for a given table.

Scans the METADATA table to determine which RangeServers hold ranges for the table with identifier id.

Parameters

context	Master context
id	Table identifier
row	Get servers containing this row ("" implies all)
servers	Reference to string set to hold RangeServer names

Definition at line 57 of file Utility.cc.

void DispatchHandlerOperationSystemStatus::initialize ( std::vector< Result > & results )

Performs initialization.

This method populates m_index with pointers to the Result objects in results. This means that while the the status operations are in progress, the caller should not modify the results vector in any way. It also starts the deadline timer m_timer.

Parameters

results Vector of result objects, one for each RangeServer.

Definition at line 37 of file DispatchHandlerOperationSystemStatus.cc.

int main	(	int	argc,
		char **	argv
	)

Read/load MML

Start timer loop

Definition at line 123 of file main.cc.

bool Hypertable::Utility::next_available_server	(	ContextPtr &	context,
		String &	location,
		bool	urgent = `false`
	)

Gets name of next available server.

Queries RangeServerConnectionManager for next available server to hold a new range and sets location to the server name if found.

Parameters

context	Master context
location	Reference to string to hold next available server name
urgent	Use servers that exceed disk threshold, if necessary

Returns: true if next available server found, false otherwise

Definition at line 304 of file Utility.cc.

void Hypertable::Utility::prepare_index	(	ContextPtr &	context,
		const String &	name,
		const String &	schema_str,
		bool	qualifier,
		String &	index_name,
		String &	index_schema
	)

Prepares index schema and table name.

Creates a schema for an index table associated with primary table name. The group commit interval is obtained from the primary table schema and copied to the index table schema. The index name is formualted by prepending "^" to the primary table name for a value index and "^^" for a qualifier index.

Parameters

context	Master context
name	Name of table for which to prepare index
schema_str	XML schema string for primary table
qualifier	Indicates if preparation is for qualifier index
index_name	Return string to hold index table name
index_schema	Return string to hold index table XML schema

Definition at line 229 of file Utility.cc.

int64_t Hypertable::Utility::range_hash_code	(	const TableIdentifier &	table,
		const RangeSpec &	range,
		const String &	qualifier
	)

Returns a hash code for a range with an optional qualifer string.

This method computes a hash code by XOR'ing the md5_hash values for the following components:

qualifier (if not empty)
table.id
range.start_row
range.end_row

Parameters

table	Table identifier
range	Range spec
qualifier	Qualifier string

Returns: Range hash code

Definition at line 379 of file Utility.cc.

String Hypertable::Utility::range_hash_string	(	const TableIdentifier &	table,
		const RangeSpec &	range,
		const String &	qualifier
	)

Returns string representation of hash code for a range with an optional qualifer string.

Calls Utility::range_hash_code and converts it to a string.

Parameters

table	Table identifier
range	Range spec
qualifier	Qualifier string

Returns: Range hash string

Definition at line 385 of file Utility.cc.

Hypertable::DispatchHandlerOperationSystemStatus::Result::Result	(	const std::string &	location,
		InetAddr	addr
	)

inline

Definition at line 54 of file DispatchHandlerOperationSystemStatus.h.

void DispatchHandlerOperationSystemStatus::result_callback ( const EventPtr & event )

overridevirtual

Handles a status request event.

Locates the corresponding result object in m_index and populates it with

Reimplemented from Hypertable::DispatchHandlerOperation.

Definition at line 51 of file DispatchHandlerOperationSystemStatus.cc.

String Hypertable::Utility::root_range_location ( ContextPtr & context )

Returns location of root METADATA range.

Reads location of root METADATA range from Location attribute of /hypertable/root file in Hyperspace and returns it.

Note: The top-level directory /hypertable may be different depending on the Hypertable.Directory property.

Parameters

context Master context

Returns: Location of root METADATA range.

Definition at line 389 of file Utility.cc.

void Hypertable::Utility::shutdown_rangeserver	(	ContextPtr &	context,
		CommAddress &	addr
	)

Sends a shutdown command to a rangeserver.

Parameters

context	Master context
addr	Address of rangeserver to shut down

Definition at line 447 of file Utility.cc.

void DispatchHandlerOperationSystemStatus::start ( const String & location )

overridevirtual

Issues a status request for the range server at location.

Parameters

location Proxy name of range server

Implements Hypertable::DispatchHandlerOperation.

Definition at line 44 of file DispatchHandlerOperationSystemStatus.cc.

bool Hypertable::Utility::status	(	ContextPtr &	context,
		Timer &	timer,
		Status &	status
	)

Runs a status check on the master.

Parameters

context	Master context
timer	Deadline timer
status	Status output object

Returns: true if status is Status::Code::OK, false otherwise

Definition at line 408 of file Utility.cc.

bool Hypertable::Utility::table_exists	(	ContextPtr &	context,
		const String &	name,
		String &	id
	)

Checks if table exists and returns table ID.

Checks to see if table name exists and returns the corresponding table ID in the id parameter. It considers the table to exist if it has an ID mapping in Hyperspace and the x attribute exists. The creation of the x atribute on a table's ID file in Hyperspace is the last thing that happens in a create table operation.

Parameters

context	Master context
name	Name of table to check for existance
id	Return parameter to hold table ID

Returns: true if table exists, false otherwise

Definition at line 100 of file Utility.cc.

bool Hypertable::Utility::table_exists	(	ContextPtr &	context,
		const String &	id
	)

Checks if table ID exists.

Checks to see if table specified by id exists. It considers the table to exist if the ID file exists in Hyperspace and the the x attribute exists. The creation of the x atribute on a table's ID file in Hyperspace is the last thing that happens in a create table operation.

Parameters

context	Master context
id	ID of table to check for existance

Returns: true if table exists, false otherwise

Definition at line 140 of file Utility.cc.

void Hypertable::Utility::verify_table_name_availability	(	ContextPtr &	context,
		const String &	name,
		String &	id
	)

Checks if table name is available.

Checks to see if table name is available for use in a create table operation. It considers the table name to be available if it does not have an ID mapping, or the x attribute does not exist. The creation of the x atribute on a table's ID file in Hyperspace is the last thing that happens in a create table operation. If this function retuns without throwing an exception, then name can be considered available. If name has an ID mapping, but no x attribute, then the ID is returned in id.

Parameters