AsyncDistributedSqlEngine:open( parameter list )

Start the connection pool, and synchronously connect all worker processes.

Prototype

 
    bool open(char const* const* nodes, int nNodes, 
            int nReplicas = 1, 
            ReplicationType replType = SQL_REPLICATION,
            int maxConnectAttempts = 10, 
            int* badNode = NULL, 
            bool localDomain = false, 
            void* sslParameters = NULL,
            timer_unit connectTimeout = 2*1000, 
            timer_unit readTimeout = 1200*1000);
 

Arguments

nodes	An array with the node names and ports ("NAME:PORT")
nNodes	The number of nodes
nReplicas	The number of replicas; this number should be a divider of nNodes meaning that the remainder of nNodes / nReplicas is 0. For example, the values of nNodes and nReplicas could be (4 and 2) or (12 and 3) but not (6 and 4) because 6 % 4 = 2
replType	The replication method
maxConnectAttempts	The maximum number of attempts to connect to the server
badNode	If this parameter is not null and the open fails, then the index of the node specification in nodes for the node that could not be connected is stored in badNode
localDomain	Indicates that Unix Domain Socket instead of networked TCP socket is used for RSQL communication which is possible only when server and client are on the same host
sslParameters	A pointer to a mco_ssl_params_t structure containing SSL connection settings
connectTimeout	The timeout for each connect attempt in milliseconds; the total connection time can be up to connectTimeout * maxConnectionAttempts milliseconds
readTimeout	The timeout for read operations in milliseconds

Description

This method opens an eXtremeDB database, an eXtremeDB SQL mapper and the AsyncDistributedSqlEngine instance with the list of parameters specified. Internally, it creates worker processes, each of which handles connections, sends queries and receives results.

Returns

This method returns true if the connection to the server was successfully established, false otherwise.

Example

     
     
    const size_t nWorkers = 4;
    const char *nodes[] = 
    {
        "localhost:5001",
        "localhost:5002"
    };
     
    int main(int argc, char** argv)
    {
        try {

            McoSql::AsyncDistributedSqlEngine engine(nWorkers);            
            if (!engine.open(nodes, sizeof(nodes) / sizeof(nodes[0]))) 
            {
                printf("Open failed: %s\n", engine.getError()->cstr());
                return 1;
            }
            ...
        }
    }