/*
* ConnectToNode opens a connection to a remote PostgreSQL server. The function
* configures the connection's fallback application name to 'pg_shard' and sets
* the remote encoding to match the local one. This function requires that the
* port be specified as a string for easier use with libpq functions.
*
* We attempt to connect up to MAX_CONNECT_ATTEMPT times. After that we give up
* and return NULL.
*/
static PGconn *
ConnectToNode(char *nodeName, char *nodePort)
{
PGconn *connection = NULL;
const char *clientEncoding = GetDatabaseEncodingName();
const char *dbname = get_database_name(MyDatabaseId);
const char *keywordArray[] = { "host", "port", "fallback_application_name",
"client_encoding", "connect_timeout", "dbname", NULL };
const char *valueArray[] = { nodeName, nodePort, "pg_shard",
clientEncoding, CLIENT_CONNECT_TIMEOUT_SECONDS, dbname, NULL };
Assert(sizeof(keywordArray) == sizeof(valueArray));
for (int attemptIndex = 0; attemptIndex < MAX_CONNECT_ATTEMPTS; attemptIndex++)
{
connection = PQconnectdbParams(keywordArray, valueArray, false);
if (PQstatus(connection) == CONNECTION_OK)
{
break;
}
else
{
/* warn if still erroring on final attempt */
if (attemptIndex == MAX_CONNECT_ATTEMPTS - 1)
{
ReportRemoteError(connection, NULL);
}
PQfinish(connection);
connection = NULL;
}
}
return connection;
}
/*
* ReraiseRemoteError retrieves error fields from a remote result and re-raises
* the error after amending it with a CONTEXT field containing the remote node
* host and port information.
*/
void
ReraiseRemoteError(PGconn *connection, PGresult *result)
{
ReportRemoteError(connection, result, true);
}
/*
* WarnRemoteError retrieves error fields from a remote result and produces an
* error report at the WARNING level after amending the error with a CONTEXT
* field containing the remote node host and port information.
*/
void
WarnRemoteError(PGconn *connection, PGresult *result)
{
ReportRemoteError(connection, result, false);
}
