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MXS-1951: Move worker selection into Listener

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The worker to which the client DCB is assigned to is now chosen by the
Listener. This makes the protocol code simpler which is always a good
thing.
This commit is contained in:
Markus Mäkelä
2019-03-19 11:19:56 +02:00
parent 5c7846da3f
commit db97c3343d
2 changed files with 25 additions and 50 deletions
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70
server/modules/protocol/MySQL/mariadbclient/mysql_client.cc
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@ -72,7 +72,6 @@ static void mysql_client_auth_error_handling(DCB* dcb, int auth_val, i
static int gw_read_do_authentication(DCB* dcb, GWBUF* read_buffer, int nbytes_read);
static int gw_read_normal_data(DCB* dcb, GWBUF* read_buffer, int nbytes_read);
static int gw_read_finish_processing(DCB* dcb, GWBUF* read_buffer, uint64_t capabilities);
static void gw_process_one_new_client(DCB* client_dcb);
static spec_com_res_t process_special_commands(DCB* client_dcb, GWBUF* read_buffer, int nbytes_read);
static spec_com_res_t handle_query_kill(DCB* dcb,
GWBUF* read_buffer,
@ -1379,61 +1378,34 @@ return_1:
}
/**
* @node Accept a new connection, using the DCB code for the basic work
* @node Accept and prepare a new client connection
*
* For as long as dcb_accept can return new client DCBs for new connections,
* continue to loop. The code will always give a failure return, since it
* continues to try to create new connections until a failure occurs.
*
* @param listener - The Listener DCB that picks up new connection requests
* @return 0 in success, 1 in failure
* @param dcb The client DCB that was created
*
* @return always 1
*/
int gw_MySQLAccept(DCB* client_dcb)
int gw_MySQLAccept(DCB* dcb)
{
gw_process_one_new_client(client_dcb);
dcb->protocol = mysql_protocol_init(dcb, dcb->fd);
MXS_ABORT_IF_NULL(dcb->protocol);
if (poll_add_dcb(dcb) == -1)
{
mysql_send_custom_error(dcb, 1, 0,
"MaxScale encountered system limit while "
"attempting to register on an epoll instance.");
MXS_ERROR("Failed to add dcb %p for fd %d to epoll set.", dcb, dcb->fd);
dcb_close(dcb);
}
else
{
MySQLSendHandshake(dcb);
}
return 1;
}
static void gw_process_one_new_client(DCB* client_dcb)
{
/**
* The worker who owns the DCB is chosen here, before any epoll events for it can be processed.
* This guarantees that the first event for the DCB is processed only after the following
* task has been processed by the owning thread.
*/
mxs::RoutingWorker* worker = mxs::RoutingWorker::pick_worker();
worker->execute([=]() {
client_dcb->protocol = mysql_protocol_init(client_dcb, client_dcb->fd);
MXS_ABORT_IF_NULL(client_dcb->protocol);
/**
* Set new descriptor to event set. At the same time,
* change state to DCB_STATE_POLLING so that
* thread which wakes up sees correct state.
*/
if (poll_add_dcb(client_dcb) == -1)
{
/* Send a custom error as MySQL command reply */
mysql_send_custom_error(client_dcb, 1, 0,
"MaxScale encountered system limit while "
"attempting to register on an epoll instance.");
/** close client_dcb */
dcb_close(client_dcb);
/** Previous state is recovered in poll_add_dcb. */
MXS_ERROR("Failed to add dcb %p for fd %d to epoll set.",
client_dcb, client_dcb->fd);
}
else
{
MySQLSendHandshake(client_dcb);
}
}, mxs::RoutingWorker::EXECUTE_AUTO);
}
static int gw_error_client_event(DCB* dcb)
{
MXS_SESSION* session;