pool_process_context.c

/* -*-pgsql-c-*- */
/*
 *
 * $Header$
 *
 * pgpool: a language independent connection pool server for PostgreSQL 
 * written by Tatsuo Ishii
 *
 * Copyright (c) 2003-2010	PgPool Global Development Group
 *
 * Permission to use, copy, modify, and distribute this software and
 * its documentation for any purpose and without fee is hereby
 * granted, provided that the above copyright notice appear in all
 * copies and that both that copyright notice and this permission
 * notice appear in supporting documentation, and that the name of the
 * author not be used in advertising or publicity pertaining to
 * distribution of the software without specific, written prior
 * permission. The author makes no representations about the
 * suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 */

#include "pool.h"
#include "pool_process_context.h"
#include "pool_config.h"		/* remove me afterwards */

static POOL_PROCESS_CONTEXT process_context_d;
static POOL_PROCESS_CONTEXT *process_context;

/*
 * Initialize per process context
 */
void pool_init_process_context(void)
{
	process_context = &process_context_d;

	if (!process_info)
	{
		pool_error("pool_init_process_context: process_info is not set");
		child_exit(1);
	}
	process_context->process_info = process_info;

	if (!pool_config->backend_desc)
	{
		pool_error("pool_init_process_context: backend_desc is not set");
		child_exit(1);
	}
	process_context->backend_desc = pool_config->backend_desc;

	process_context->proc_id = my_proc_id;

	process_context->local_session_id = 0;		/* initialize local session counter */
}

/*
 * Return process context
 */
POOL_PROCESS_CONTEXT *pool_get_process_context(void)
{
	if (!process_context)
	{
		pool_error("pool_get_process_context: process context is not initialized");
	}
	return process_context;
}

/*
 * Return my process info
 */
ProcessInfo *pool_get_my_process_info(void)
{
	if (!process_context)
	{
		pool_error("pool_get_my_process_info: process context is not initialized");
		return NULL;
	}

	return &process_context->process_info[process_context->proc_id];
}

/*
 * Increment local session id
 */
void pool_incremnet_local_session_id(void)
{
	POOL_PROCESS_CONTEXT *p = pool_get_process_context();

	if (!p)
	{
		pool_error("pool_incremnet_local_session_id: cannot get process context");
		return;
	}
	p->local_session_id++;
}

/*
 * Return byte size of connection info(ConnectionInfo) on shmem.
 */
int pool_coninfo_size(void)
{
	int size;
	size = pool_config->num_init_children *
		pool_config->max_pool *
		MAX_NUM_BACKENDS *
		sizeof(ConnectionInfo);

	return size;
}

/*
 * Return number of elements of connection info(ConnectionInfo) on shmem.
 */
int pool_coninfo_num(void)
{
	int nelm;
	nelm = pool_config->num_init_children *
		pool_config->max_pool *
		MAX_NUM_BACKENDS;

	return nelm;
}

/*
 * Return pointer to i th child, j th connection pool and k th backend
 * of connection info on shmem.
 */
ConnectionInfo *pool_coninfo(int child, int connection_pool, int backend)
{
	if (child < 0 || child >= pool_config->num_init_children)
	{
		pool_error("pool_coninfo: invalid child number: %d", child);
		return NULL;
	}

	if (connection_pool < 0 || connection_pool >= pool_config->max_pool)
	{
		pool_error("pool_coninfo: invalid connection_pool number: %d", connection_pool);
		return NULL;
	}

	if (backend < 0 || backend >= MAX_NUM_BACKENDS)
	{
		pool_error("pool_coninfo: invalid backend number: %d", backend);
		return NULL;
	}

	return &con_info[child*pool_config->max_pool*MAX_NUM_BACKENDS+
					 connection_pool*MAX_NUM_BACKENDS+
					 backend];
}

/*
 * Return pointer to child which has OS process id pid, j th connection
 * pool and k th backend of connection info on shmem.
 */
ConnectionInfo *pool_coninfo_pid(int pid, int connection_pool, int backend)
{
	int child = -1;
	int		i;

	for (i = 0; i < pool_config->num_init_children; i++)
	{
		if (process_info[i].pid == pid)
		{
			child = i;
			break;
		}
	}

	if (child < 0)
	{
		pool_error("pool_coninfo_pid: invalid child pid: %d", pid);
		return NULL;
	}

	if (child < 0 || child >= pool_config->num_init_children)
	{
		pool_error("pool_coninfo_pid: invalid child number: %d", child);
		return NULL;
	}

	if (connection_pool < 0 || connection_pool >= pool_config->max_pool)
	{
		pool_error("pool_coninfo_pid: invalid connection_pool number: %d", connection_pool);
		return NULL;
	}

	if (backend < 0 || backend >= MAX_NUM_BACKENDS)
	{
		pool_error("pool_coninfo: invalid backend number: %d", backend);
		return NULL;
	}

	return &con_info[child*pool_config->max_pool*MAX_NUM_BACKENDS+
					 connection_pool*MAX_NUM_BACKENDS+
					 backend];
}

/*
 * Set frontend connected flag
 */
void pool_coninfo_set_frontend_connected(int proc_id, int pool_index)
{
	ConnectionInfo *con;
	int i;

	for (i=0;i<NUM_BACKENDS;i++)
	{
		con = pool_coninfo(proc_id, pool_index, i);

		if (con == NULL)
		{
			pool_error("pool_coninfo_set_frontend_connected: cannot get ConnectionInfo");
			return;
		}
		con->connected = true;
	}
}

/*
 * Unset frontend connected flag
 */
void pool_coninfo_unset_frontend_connected(int proc_id, int pool_index)
{
	ConnectionInfo *con;
	int i;

	for (i=0;i<NUM_BACKENDS;i++)
	{
		con = pool_coninfo(proc_id, pool_index, i);

		if (con == NULL)
		{
			pool_error("pool_coninfo_unset_frontend_connected: cannot get ConnectionInfo");
			return;
		}
		con->connected = false;
	}
}