ConnectionManager Class Reference

Singleton class to manage Postgres connection pool. More...

#include <connection_manager.h>

Collaboration diagram for ConnectionManager:

Public Member Functions
void	growPool (unsigned int)
	Grow the connection pool by the number of connections specified. More...
unsigned int	shrinkPool (unsigned int)
	Attempt to shrink the number of connections in the idle pool. More...
Connection *	allocate ()
	Allocate a connection from the idle pool. More...
void	release (Connection *)
	Release a connection back to the idle pool for reallocation. More...
void	shutdown ()
	Called at shutdown. More...
void	setError (const char *, const char *, bool)
	Set the last error information for a plugin. More...
PLUGIN_ERROR *	getError ()
void	setMaxReadingRows (long rows)
void	growPool (unsigned int)
unsigned int	shrinkPool (unsigned int)
Connection *	allocate ()
bool	attachNewDb (std::string &path, std::string &alias)
	Attach a database to all the connections, idle and inuse. More...
bool	attachRequestNewDb (int newDbId, sqlite3 *dbHandle)
	Adds to all the connections a request to attach a database. More...
bool	detachNewDb (std::string &alias)
	Detach a database from all the connections. More...
void	release (Connection *)
void	shutdown ()
void	setError (const char *, const char *, bool)
PLUGIN_ERROR *	getError ()
void	background ()
	Background thread used to execute periodic tasks and oversee the database activity. More...
void	setVacuumInterval (long hours)
bool	allowMoreDatabases ()
	Determine if we can allow another database to be created and attached to all the connections. More...
void	setConfiguration (ConfigCategory *category)
std::string	getDBConfiguration ()
	Return the pragma configuration for the database.
void	growPool (unsigned int)
unsigned int	shrinkPool (unsigned int)
Connection *	allocate ()
void	release (Connection *)
void	shutdown ()
void	setError (const char *, const char *, bool)
PLUGIN_ERROR *	getError ()
void	background ()
void	setVacuumInterval (long hours)
void	setPersist (bool persist, const std::string &filename="")
bool	persist ()
std::string	filename ()
void	setPurgeBlockSize (unsigned long purgeBlockSize)
	Set the purge block size in each of the connections. More...

Static Public Member Functions
static ConnectionManager *	getInstance ()
	Return the singleton instance of the connection manager. More...
static ConnectionManager *	getInstance ()
static ConnectionManager *	getInstance ()

Protected Attributes
bool	m_trace
bool	m_shutdown
std::thread *	m_background
long	m_vacuumInterval
unsigned int	m_descriptorLimit
unsigned int	m_attachedDatabases
DiskSpaceMonitor *	m_diskSpaceMonitor
ConfigCategory *	m_config
bool	m_persist
std::string	m_filename
unsigned long	m_purgeBlockSize

Detailed Description

Singleton class to manage Postgres connection pool.

Singleton class to manage SQLite3 connection pool.

Member Function Documentation

allocate()

Connection * ConnectionManager::allocate

(

)

Allocate a connection from the idle pool.

If no connection is available add a new connection

allowMoreDatabases()

bool ConnectionManager::allowMoreDatabases

(

)

Determine if we can allow another database to be created and attached to all the connections.

Returns

True if we can create another database.

attachNewDb()

bool ConnectionManager::attachNewDb	(	std::string &	path,
		std::string &	alias
	)

Attach a database to all the connections, idle and inuse.

Parameters

path	- path of the database to attach
alias	- alias to be assigned to the attached database

attachRequestNewDb()

bool ConnectionManager::attachRequestNewDb	(	int	newDbId,
		sqlite3 *	dbHandle
	)

Adds to all the connections a request to attach a database.

• Parameters

  newDbId	- database id to attach
  dbHandle	- dbhandle for which the attach request should NOT be added

background()

void ConnectionManager::background

(

)

Background thread used to execute periodic tasks and oversee the database activity.

We will run the SQLite vacuum command periodically to allow space to be reclaimed

We will runt he SQLite vacuum command periodically to allow space to be reclaimed

detachNewDb()

bool ConnectionManager::detachNewDb

(

std::string &

alias

)

Detach a database from all the connections.

getInstance()

ConnectionManager * ConnectionManager::getInstance ( )

static

Return the singleton instance of the connection manager.

if none was created then create it.

growPool()

void ConnectionManager::growPool

(

unsigned int

delta

)

Grow the connection pool by the number of connections specified.

Parameters

delta

The number of connections to add to the pool

release()

void ConnectionManager::release

(

Connection *

conn

)

Release a connection back to the idle pool for reallocation.

Parameters

conn	The connection to release.

setError()

void ConnectionManager::setError	(	const char *	source,
		const char *	description,
		bool	retryable
	)

Set the last error information for a plugin.

Parameters

source	The source of the error
description	The error description
retryable	Flag to determien if the error condition is transient

setPurgeBlockSize()

void ConnectionManager::setPurgeBlockSize

(

unsigned long

purgeBlockSize

)

Set the purge block size in each of the connections.

Parameters

purgeBlockSize

The requested purgeBlockSize

shrinkPool()

unsigned int ConnectionManager::shrinkPool

(

unsigned int

delta

)

Attempt to shrink the number of connections in the idle pool.

Parameters

delta

Number of connections to attempt to remove

Returns

The number of connections removed.

shutdown()

void ConnectionManager::shutdown

(

)

Called at shutdown.

Shrink the idle pool, this will have the side effect of closing the connections to the database.

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The documentation for this class was generated from the following files:

• C/plugins/storage/postgres/include/connection_manager.h
• C/plugins/storage/postgres/connection_manager.cpp