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Code Releases Wiki Activity

feature #2245: Allow multiple MySQL connections

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This commit is contained in:
Ruben S. Montero 2013-09-11 12:38:58 +02:00
parent f77ec81fb8
commit 59bbb3b156
3 changed files with 140 additions and 44 deletions
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38
include/MySqlDB.h
View File

@ -20,6 +20,7 @@
#include <string>
#include <sstream>
#include <stdexcept>
#include <queue>
#include <sys/time.h>
#include <sys/types.h>
@ -77,9 +78,19 @@ public:
private:
/**
* The MySql connection handler
* Number of concurrent DB connections.
*/
MYSQL * db;
static const int DB_CONNECT_SIZE;
/**
* The MySql connection pool handler
*/
queue<MYSQL *> db_connect;
/**
* Cached DB connection to escape strings (it uses the server character set)
*/
MYSQL * db_escape_connect;
/**
* MySQL Connection parameters
@ -95,25 +106,24 @@ private:
string database;
/**
* Fine-grain mutex for DB access
* Fine-grain mutex for DB access (pool of DB connections)
*/
pthread_mutex_t mutex;
pthread_mutex_t mutex;
/**
* Function to lock the DB
* Conditional variable to wake-up waiting threads.
*/
void lock()
{
pthread_mutex_lock(&mutex);
};
pthread_cond_t cond;
/**
* Function to unlock the DB
* Gets a free DB connection from the pool.
*/
void unlock()
{
pthread_mutex_unlock(&mutex);
};
MYSQL * get_db_connection();
/**
* Returns the connection to the pool.
*/
void free_db_connection(MYSQL * db);
};
#else
//CLass stub

16
src/nebula/Nebula.cc
View File

@ -454,22 +454,6 @@ void Nebula::start()
ostringstream oss;
db = new MySqlDB(server,port,user,passwd,db_name);
oss << "CREATE DATABASE IF NOT EXISTS " << db_name;
rc = db->exec(oss);
if ( rc != 0 )
{
throw runtime_error("Could not create database.");
}
oss.str("");
oss << "USE " << db_name;
rc = db->exec(oss);
if ( rc != 0 )
{
throw runtime_error("Could not open database.");
}
}
// ---------------------------------------------------------------------

130
src/sql/MySqlDB.cc
View File

@ -21,6 +21,8 @@
* Doc: http://dev.mysql.com/doc/refman/5.5/en/c-api-function-overview.html
********/
const int MySqlDB::DB_CONNECT_SIZE = 10;
/* -------------------------------------------------------------------------- */
MySqlDB::MySqlDB(
@ -30,6 +32,11 @@ MySqlDB::MySqlDB(
const string& _password,
const string& _database)
{
vector<MYSQL *> connections(DB_CONNECT_SIZE);
MYSQL * rc;
ostringstream oss;
server = _server;
port = _port;
user = _user;
@ -39,30 +46,88 @@ MySqlDB::MySqlDB(
// Initialize the MySQL library
mysql_library_init(0, NULL, NULL);
// Initialize a connection handler
db = mysql_init(NULL);
// Connect to the server
if (!mysql_real_connect(db, server.c_str(), user.c_str(),
password.c_str(), 0, port, NULL, 0))
// Create connection pool to the server
for (int i=0 ; i < DB_CONNECT_SIZE ; i++)
{
throw runtime_error("Could not open database.");
connections[i] = mysql_init(NULL);
rc = mysql_real_connect(connections[i],
server.c_str(),
user.c_str(),
password.c_str(),
0,
port,
NULL,
0);
if ( rc == NULL)
{
throw runtime_error("Could not open connect to database server.");
}
}
db_escape_connect = mysql_init(NULL);
rc = mysql_real_connect(db_escape_connect,
server.c_str(),
user.c_str(),
password.c_str(),
0,
port,
NULL,
0);
if ( rc == NULL)
{
throw runtime_error("Could not open connect to database server.");
}
//Connect to the database & initialize connection pool
oss << "CREATE DATABASE IF NOT EXISTS " << database;
if ( mysql_query(connections[0], oss.str().c_str()) != 0 )
{
throw runtime_error("Could not create the database.");
}
oss.str("");
oss << "USE " << database;
for (int i=0 ; i < DB_CONNECT_SIZE ; i++)
{
if ( mysql_query(connections[i], oss.str().c_str()) != 0 )
{
throw runtime_error("Could not connect to the database.");
}
db_connect.push(connections[i]);
}
pthread_mutex_init(&mutex,0);
pthread_cond_init(&cond,0);
}
/* -------------------------------------------------------------------------- */
MySqlDB::~MySqlDB()
{
// Close the connection to the MySQL server
mysql_close(db);
// Close the connections to the MySQL server
while (!db_connect.empty())
{
MYSQL * db = db_connect.front();
db_connect.pop();
mysql_close(db);
}
mysql_close(db_escape_connect);
// End use of the MySQL library
mysql_library_end();
pthread_mutex_destroy(&mutex);
pthread_cond_destroy(&cond);
}
/* -------------------------------------------------------------------------- */
@ -77,7 +142,9 @@ int MySqlDB::exec(ostringstream& cmd, Callbackable* obj)
str = cmd.str();
c_str = str.c_str();
lock();
MYSQL *db;
db = get_db_connection();
rc = mysql_query(db, c_str);
@ -111,7 +178,7 @@ int MySqlDB::exec(ostringstream& cmd, Callbackable* obj)
NebulaLog::log("ONE",Log::ERROR,oss);
unlock();
free_db_connection(db);
return -1;
}
@ -139,7 +206,7 @@ int MySqlDB::exec(ostringstream& cmd, Callbackable* obj)
NebulaLog::log("ONE",Log::ERROR,oss);
unlock();
free_db_connection(db);
return -1;
}
@ -167,7 +234,7 @@ int MySqlDB::exec(ostringstream& cmd, Callbackable* obj)
delete[] names;
}
unlock();
free_db_connection(db);
return 0;
}
@ -178,7 +245,7 @@ char * MySqlDB::escape_str(const string& str)
{
char * result = new char[str.size()*2+1];
mysql_real_escape_string(db, result, str.c_str(), str.size());
mysql_real_escape_string(db_escape_connect, result, str.c_str(), str.size());
return result;
}
@ -191,3 +258,38 @@ void MySqlDB::free_str(char * str)
}
/* -------------------------------------------------------------------------- */
MYSQL * MySqlDB::get_db_connection()
{
MYSQL *db;
pthread_mutex_lock(&mutex);
while ( db_connect.empty() == true )
{
pthread_cond_wait(&cond, &mutex);
}
db = db_connect.front();
db_connect.pop();
pthread_mutex_unlock(&mutex);
return db;
}
/* -------------------------------------------------------------------------- */
void MySqlDB::free_db_connection(MYSQL * db)
{
pthread_mutex_lock(&mutex);
db_connect.push(db);
pthread_cond_signal(&cond);
pthread_mutex_unlock(&mutex);
}
/* -------------------------------------------------------------------------- */