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Added new state to SESSION: SESSION_STATE_STOPPING, which is set in protocol module before calling closeSession (router). THe new state tells that session is closing and DCBs included may not be polling anymore.

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Fixed some crash scenarios.
This commit is contained in:
VilhoRaatikka 2014-05-08 23:17:35 +03:00
parent a1361d9c9e
commit 8be4aba223
8 changed files with 216 additions and 113 deletions
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15
server/core/dbusers.c
View File

@ -217,15 +217,26 @@ getUsers(SERVICE *service, struct users *users)
*/
server = service->databases;
dpwd = decryptPassword(service_passwd);
while (server != NULL && mysql_real_connect(con,
while (server != NULL && (mysql_real_connect(con,
server->name,
service_user,
dpwd,
NULL,
server->port,
NULL,
0) == NULL)
0) == NULL))
{
if (server == NULL)
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Unable to connect to %s:%d, \"%s\"",
server->name,
server->port,
mysql_error(con))));
mysql_close(con);
return -1;
}
server = server->nextdb;
}
free(dpwd);

12
server/core/dcb.c
View File

@ -688,11 +688,20 @@ dcb_write(DCB *dcb, GWBUF *queue)
ss_dassert(queue != NULL);
/**
* SESSION_STATE_STOPPING means that one of the backends is closing
* the router session. Some backends may have not completed
* authentication yet and thus they have no information about router
* being closed. Session state is changed to SESSION_STATE_STOPPING
* before router's closeSession is called and that tells that DCB may
* still be writable.
*/
if (queue == NULL ||
(dcb->state != DCB_STATE_ALLOC &&
dcb->state != DCB_STATE_POLLING &&
dcb->state != DCB_STATE_LISTENING &&
dcb->state != DCB_STATE_NOPOLLING))
dcb->state != DCB_STATE_NOPOLLING &&
dcb->session->state != SESSION_STATE_STOPPING))
{
LOGIF(LD, (skygw_log_write(
LOGFILE_DEBUG,
@ -703,6 +712,7 @@ dcb_write(DCB *dcb, GWBUF *queue)
dcb,
STRDCBSTATE(dcb->state),
dcb->fd)));
ss_dassert(false);
return 0;
}

19
server/core/session.c
View File

@ -129,6 +129,10 @@ session_alloc(SERVICE *service, DCB *client_dcb)
session);
if (session->router_session == NULL) {
/**
* Inform other threads that session is closing.
*/
session->state == SESSION_STATE_STOPPING;
/*<
* Decrease refcount, set dcb's session pointer NULL
* and set session pointer to NULL.
@ -439,3 +443,18 @@ session_state(int state)
return "Invalid State";
}
}
SESSION* get_session_by_router_ses(
void* rses)
{
SESSION* ses = allSessions;
while (ses->router_session != rses && ses->next != NULL)
ses = ses->next;
if (ses->router_session != rses)
{
ses = NULL;
}
return ses;
}

4
server/include/session.h
View File

@ -53,6 +53,7 @@ typedef enum {
SESSION_STATE_ALLOC, /*< for all sessions */
SESSION_STATE_READY, /*< for router session */
SESSION_STATE_ROUTER_READY, /*< for router session */
SESSION_STATE_STOPPING, /*< router is being closed */
SESSION_STATE_LISTENER, /*< for listener session */
SESSION_STATE_LISTENER_STOPPED, /*< for listener session */
SESSION_STATE_FREE /*< for all sessions */
@ -93,4 +94,5 @@ void dprintAllSessions(struct dcb *);
void dprintSession(struct dcb *, SESSION *);
char *session_state(int);
bool session_link_dcb(SESSION *, struct dcb *);
#endif
SESSION* get_session_by_router_ses(void* rses);
#endif

56
server/modules/protocol/mysql_backend.c
View File

@ -306,12 +306,14 @@ static int gw_read_backend_event(DCB *dcb) {
/* try reload users' table for next connection */
service_refresh_users(dcb->session->client->service);
while (session->state != SESSION_STATE_ROUTER_READY)
while (session->state != SESSION_STATE_ROUTER_READY &&
session->state != SESSION_STATE_STOPPING)
{
ss_dassert(
session->state == SESSION_STATE_READY ||
session->state ==
SESSION_STATE_ROUTER_READY);
SESSION_STATE_ROUTER_READY ||
session->state == SESSION_STATE_STOPPING);
/**
* Session shouldn't be NULL at this point
* anymore. Just checking..
@ -323,6 +325,15 @@ static int gw_read_backend_event(DCB *dcb) {
}
usleep(1);
}
if (session->state == SESSION_STATE_STOPPING)
{
goto return_with_lock;
}
spinlock_acquire(&session->ses_lock);
session->state = SESSION_STATE_STOPPING;
spinlock_release(&session->ses_lock);
/**
* rsession shouldn't be NULL since session
* state indicates that it was initialized
@ -357,8 +368,7 @@ static int gw_read_backend_event(DCB *dcb) {
/* check the delay queue and flush the data */
if (dcb->delayq)
{
backend_write_delayqueue(dcb);
rc = 1;
rc = backend_write_delayqueue(dcb);
goto return_with_lock;
}
}
@ -567,9 +577,7 @@ gw_MySQLWrite_backend(DCB *dcb, GWBUF *queue)
snprintf(str, len+1, "%s", startpoint);
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Routing query \"%s\" failed due to "
"authentication failure.",
str)));
"Error : Authentication to backend failed.")));
/** Consume query buffer */
while ((queue = gwbuf_consume(
queue,
@ -667,6 +675,10 @@ static int gw_error_backend_event(DCB *dcb) {
if (session->state == SESSION_STATE_ROUTER_READY)
{
spinlock_acquire(&session->ses_lock);
session->state = SESSION_STATE_STOPPING;
spinlock_release(&session->ses_lock);
rsession = session->router_session;
/*<
* rsession should never be NULL here.
@ -847,34 +859,36 @@ static int backend_write_delayqueue(DCB *dcb)
spinlock_acquire(&dcb->delayqlock);
if (dcb->delayq == NULL)
{
spinlock_release(&dcb->delayqlock);
rc = 1;
}
else
{
localq = dcb->delayq;
dcb->delayq = NULL;
spinlock_release(&dcb->delayqlock);
rc = dcb_write(dcb, localq);
}
if (rc == 0) {
/*< vraa : errorHandle */
/**
* This error can be muted because it is often due
* unexpected dcb state which means that concurrent thread
* already wrote the queue and closed dcb.
*/
#if 0
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"%lu [backend_write_delayqueue] Some error occurred in "
"backend.",
pthread_self())));
#endif
"Error : failed to write buffered data to back-end "
"server. Buffer was empty of back-end was disconnected "
"during operation.")));
mysql_send_custom_error(
dcb->session->client,
1,
0,
"Unable to write to backend server. Connection was "
"closed.");
"Failed to write buffered data to back-end server. "
"Buffer was empty or back-end was disconnected during "
"operation.");
dcb_close(dcb);
}
return rc;
}

96
server/modules/protocol/mysql_client.c
View File

@ -540,7 +540,7 @@ int gw_read_client_event(DCB* dcb) {
goto return_rc;
}
// close client socket and the sessioA too
// close client socket and the session too
dcb->func.close(dcb);
} else {
// do nothing if reading 1 byte
@ -731,12 +731,8 @@ int gw_read_client_event(DCB* dcb) {
"backend. Close client dcb %p",
pthread_self(),
dcb)));
/** close client connection */
(dcb->func).close(dcb);
/** close backends connection */
router->closeSession(router_instance, rsession);
rc = 1;
/** close client connection, closes router session too */
rc = dcb->func.close(dcb);
}
else
{
@ -1217,37 +1213,16 @@ return_rc:
return rc;
}
static int gw_error_client_event(DCB *dcb) {
SESSION* session;
ROUTER_OBJECT* router;
void* router_instance;
void* rsession;
#if defined(SS_DEBUG)
MySQLProtocol* protocol = (MySQLProtocol *)dcb->protocol;
if (dcb->state == DCB_STATE_POLLING ||
dcb->state == DCB_STATE_NOPOLLING ||
dcb->state == DCB_STATE_ZOMBIE)
{
CHK_PROTOCOL(protocol);
}
#endif
session = dcb->session;
/**
* session may be NULL if session_alloc failed.
* In that case router session was not created.
*/
if (session != NULL) {
CHK_SESSION(session);
router = session->service->router;
router_instance = session->service->router_instance;
rsession = session->router_session;
router->closeSession(router_instance, rsession);
}
dcb_close(dcb);
return 1;
static int gw_error_client_event(
DCB* dcb)
{
int rc;
CHK_DCB(dcb);
rc = dcb->func.close(dcb);
return rc;
}
static int
@ -1274,6 +1249,10 @@ gw_client_close(DCB *dcb)
*/
if (session != NULL) {
CHK_SESSION(session);
spinlock_acquire(&session->ses_lock);
session->state = SESSION_STATE_STOPPING;
spinlock_release(&session->ses_lock);
router = session->service->router;
router_instance = session->service->router_instance;
rsession = session->router_session;
@ -1296,43 +1275,12 @@ gw_client_close(DCB *dcb)
static int
gw_client_hangup_event(DCB *dcb)
{
SESSION* session;
ROUTER_OBJECT* router;
void* router_instance;
void* rsession;
int rc = 1;
#if defined(SS_DEBUG)
MySQLProtocol* protocol = (MySQLProtocol *)dcb->protocol;
if (dcb->state == DCB_STATE_POLLING ||
dcb->state == DCB_STATE_NOPOLLING ||
dcb->state == DCB_STATE_ZOMBIE)
{
CHK_PROTOCOL(protocol);
}
#endif
CHK_DCB(dcb);
int rc;
if (dcb->state != DCB_STATE_POLLING) {
goto return_rc;
}
session = dcb->session;
/**
* session may be NULL if session_alloc failed.
* In that case router session was not created.
*/
if (session != NULL) {
CHK_SESSION(session);
router = session->service->router;
router_instance = session->service->router_instance;
rsession = session->router_session;
router->closeSession(router_instance, rsession);
}
dcb_close(dcb);
return_rc:
return rc;
CHK_DCB(dcb);
rc = dcb->func.close(dcb);
return rc;
}

2
server/modules/protocol/mysql_common.c
View File

@ -605,7 +605,7 @@ int gw_do_connect_to_backend(
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error: Establishing connection to backend server "
"%s:%d failed. Socket creation failed due "
"%s:%d failed.\n\t\t Socket creation failed due "
"%d, %s.",
host,
port,

125
server/modules/routing/readwritesplit/readwritesplit.c
View File

@ -503,6 +503,7 @@ static void* newSession(
{
/** log this */
free(client_rses);
free(backend_ref);
client_rses = NULL;
goto return_rses;
}
@ -609,7 +610,7 @@ static void closeSession(
backend_ref_t* backend_ref;
router_cli_ses = (ROUTER_CLIENT_SES *)router_session;
CHK_CLIENT_RSES(router_cli_ses);
CHK_CLIENT_RSES(router_cli_ses);
backend_ref = router_cli_ses->rses_backend_ref;
/**
@ -618,8 +619,17 @@ static void closeSession(
if (!router_cli_ses->rses_closed &&
rses_begin_locked_router_action(router_cli_ses))
{
DCB* dcbs[router_cli_ses->rses_nbackends];
int i = 0;
/**
* session must be moved to SESSION_STATE_STOPPING state before
* router session is closed.
*/
#if defined(SS_DEBUG)
SESSION* ses = get_session_by_router_ses((void*)router_cli_ses);
ss_dassert(ses != NULL);
ss_dassert(ses->state == SESSION_STATE_STOPPING);
#endif
/**
* This sets router closed. Nobody is allowed to use router
@ -629,17 +639,18 @@ static void closeSession(
for (i=0; i<router_cli_ses->rses_nbackends; i++)
{
DCB* dcb = backend_ref[i].bref_dcb;
/** decrease server current connection counters */
atomic_add(&backend_ref[i].bref_backend->backend_server->stats.n_current, -1);
/** Close those which had been connected */
if (backend_ref[i].bref_dcb != NULL)
if (dcb != NULL)
{
CHK_DCB(backend_ref[i].bref_dcb);
dcbs[i] = backend_ref[i].bref_dcb;
CHK_DCB(dcb);
backend_ref[i].bref_dcb =
(DCB *)0xdeadbeef; /*< prevent new uses of DCB */
dcbs[i]->func.close(dcbs[i]);
dcb->func.close(dcb);
}
}
/** Unlock */
@ -743,6 +754,29 @@ static bool get_dcb(
succp = true;
}
}
if (!succp)
{
backend_ref = rses->rses_master_ref;
if (backend_ref->bref_dcb != NULL)
{
*p_dcb = backend_ref->bref_dcb;
succp = true;
ss_dassert(
SERVER_IS_MASTER(backend_ref->bref_backend->backend_server) &&
smallest_nconn == -1);
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Warning : No slaves connected nor "
"available. Choosing master %s:%d "
"instead.",
backend_ref->bref_backend->backend_server->name,
backend_ref->bref_backend->backend_server->port)));
}
}
ss_dassert(succp);
}
else if (btype == BE_MASTER || BE_JOINED)
@ -962,16 +996,29 @@ static int routeQuery(
if (succp)
{
/** Lock router session */
if (!rses_begin_locked_router_action(router_cli_ses))
{
goto return_ret;
}
if ((ret = slave_dcb->func.write(slave_dcb, querybuf)) == 1)
{
atomic_add(&inst->stats.n_slave, 1);
}
ss_dassert(ret == 1);
else
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Routing query \"%s\" failed.",
querystr)));
}
rses_end_locked_router_action(router_cli_ses);
}
ss_dassert(succp);
goto return_ret;
}
else
}
else
{
bool succp = true;
@ -998,10 +1045,17 @@ static int routeQuery(
}
if (succp)
{
/** Lock router session */
if (!rses_begin_locked_router_action(router_cli_ses))
{
goto return_ret;
}
if ((ret = master_dcb->func.write(master_dcb, querybuf)) == 1)
{
atomic_add(&inst->stats.n_master, 1);
}
rses_end_locked_router_action(router_cli_ses);
}
ss_dassert(succp);
ss_dassert(ret == 1);
@ -1316,6 +1370,18 @@ static bool select_connect_backend_servers(
is_synced_master = false;
}
LOGIF(LT, (skygw_log_write(LOGFILE_TRACE, "Servers and conns before ordering:")));
for (i=0; i<router_nservers; i++)
{
BACKEND* b = backend_ref[i].bref_backend;
LOGIF(LT, (skygw_log_write(LOGFILE_TRACE,
"%s %d:%d",
b->backend_server->name,
b->backend_server->port,
b->backend_conn_count)));
}
/**
* Sort the pointer list to servers according to connection counts. As
* a consequence those backends having least connections are in the
@ -1323,6 +1389,19 @@ static bool select_connect_backend_servers(
*/
qsort((void *)backend_ref, (size_t)router_nservers, sizeof(backend_ref_t), bref_cmp);
LOGIF(LT, (skygw_log_write(LOGFILE_TRACE, "Servers and conns after ordering:")));
for (i=0; i<router_nservers; i++)
{
BACKEND* b = backend_ref[i].bref_backend;
LOGIF(LT, (skygw_log_write(LOGFILE_TRACE,
"%s %d:%d",
b->backend_server->name,
b->backend_server->port,
b->backend_conn_count)));
}
/**
* Choose at least 1+1 (master and slave) and at most 1+max_nslaves
* servers from the sorted list. First master found is selected.
@ -1366,6 +1445,12 @@ static bool select_connect_backend_servers(
}
else
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Unable to establish "
"connection with slave %s:%d",
b->backend_server->name,
b->backend_server->port)));
/* handle connect error */
}
}
@ -1389,6 +1474,13 @@ static bool select_connect_backend_servers(
}
else
{
succp = false;
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Unable to establish "
"connection with master %s:%d",
b->backend_server->name,
b->backend_server->port)));
/* handle connect error */
}
}
@ -1929,8 +2021,7 @@ static bool execute_sescmd_in_backend(
dcb->session,
sescmd_cursor_clone_querybuf(scur));
break;
case COM_QUIT:
case COM_QUERY:
case COM_INIT_DB:
default:
@ -2153,7 +2244,14 @@ static bool route_session_write(
int rc;
succp = true;
/** Lock router session */
if (!rses_begin_locked_router_action(router_cli_ses))
{
succp = false;
goto return_succp;
}
for (i=0; i<router_cli_ses->rses_nbackends; i++)
{
DCB* dcb = backend_ref[i].bref_dcb;
@ -2168,6 +2266,7 @@ static bool route_session_write(
}
}
}
rses_end_locked_router_action(router_cli_ses);
gwbuf_free(querybuf);
goto return_succp;
}