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Complementary fix to #694,http://bugs.mariadb.com/show_bug.cgi?id=694

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RWSplit router handles query processing errors that happened in router by sending parse error reply to client. routeQuery fails only when backend has failed.
This commit is contained in:
VilhoRaatikka 2015-01-17 22:40:52 +02:00
parent d362ed227f
commit 6d2b38d4b6
6 changed files with 106 additions and 36 deletions
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71
server/core/modutil.c
View File

@ -32,6 +32,19 @@
#include <string.h>
#include <mysql_client_server_protocol.h>
#include <modutil.h>
/** Defined in log_manager.cc */
extern int lm_enabled_logfiles_bitmask;
extern size_t log_ses_count[];
extern __thread log_info_t tls_log_info;
static void modutil_reply_routing_error(
DCB* backend_dcb,
int error,
char* state,
char* errstr);
/**
* Check if a GWBUF structure is a MySQL COM_QUERY packet
*
@ -327,7 +340,7 @@ GWBUF *modutil_create_mysql_err_msg(
const char *msg)
{
uint8_t *outbuf = NULL;
uint32_t mysql_payload_size = 0;
uint32_t mysql_payload_size = 0;
uint8_t mysql_packet_header[4];
uint8_t *mysql_payload = NULL;
uint8_t field_count = 0;
@ -528,7 +541,7 @@ modutil_count_signal_packets(GWBUF *reply, int use_ok, int n_found)
unsigned char* ptr = (unsigned char*) reply->start;
unsigned char* end = (unsigned char*) reply->end;
unsigned char* prev = ptr;
int pktlen, eof = 0, err = 0, found = n_found;
int pktlen, eof = 0, err = 0;
int errlen = 0, eoflen = 0;
int iserr = 0, iseof = 0;
while(ptr < end)
@ -583,3 +596,57 @@ modutil_count_signal_packets(GWBUF *reply, int use_ok, int n_found)
return(eof + err);
}
/**
* Create parse error and EPOLLIN event to event queue of the backend DCB.
* When event is notified the error message is processed as error reply and routed
* upstream to client.
*
* @param backend_dcb DCB where event is added
* @param errstr Plain-text string error
*/
void modutil_reply_parse_error(
DCB* backend_dcb,
char* errstr)
{
CHK_DCB(backend_dcb);
modutil_reply_routing_error(backend_dcb, 1064, "42000", errstr);
}
/**
* Create error message and EPOLLIN event to event queue of the backend DCB.
* When event is notified the message is processed as error reply and routed
* upstream to client.
*
* @param backend_dcb DCB where event is added
* @param error SQL error number
* @param state SQL state
* @param errstr Plain-text string error
*/
static void modutil_reply_routing_error(
DCB* backend_dcb,
int error,
char* state,
char* errstr)
{
GWBUF* buf;
CHK_DCB(backend_dcb);
buf = modutil_create_mysql_err_msg(1, 0, error, state, errstr);
free(errstr);
if (buf == NULL)
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Creating buffer for error message failed.")));
return;
}
/** Set flags that help router to identify session commands reply */
gwbuf_set_type(buf, GWBUF_TYPE_MYSQL);
gwbuf_set_type(buf, GWBUF_TYPE_SESCMD_RESPONSE);
gwbuf_set_type(buf, GWBUF_TYPE_RESPONSE_END);
/** Create an incoming event for backend DCB */
poll_add_epollin_event_to_dcb(backend_dcb, buf);
return;
}

1
server/include/modutil.h
View File

@ -50,6 +50,7 @@ extern int modutil_send_mysql_err_packet(DCB *, int, int, int, const char *, con
GWBUF* modutil_get_next_MySQL_packet(GWBUF** p_readbuf);
GWBUF* modutil_get_complete_packets(GWBUF** p_readbuf);
int modutil_MySQL_query_len(GWBUF* buf, int* nbytes_missing);
void modutil_reply_parse_error(DCB* backend_dcb, char* errstr);
GWBUF *modutil_create_mysql_err_msg(
int packet_number,

12
server/include/router.h
View File

@ -43,6 +43,11 @@
*/
typedef void *ROUTER;
typedef enum error_action {
ERRACT_NEW_CONNECTION = 0x001,
ERRACT_REPLY_CLIENT = 0x002,
ERRACT_RESET = 0x004
} error_action_t;
/**
* @verbatim
@ -66,13 +71,6 @@ typedef void *ROUTER;
*
* @see load_module
*/
typedef enum error_action {
ERRACT_NEW_CONNECTION = 0x001,
ERRACT_REPLY_CLIENT = 0x002,
ERRACT_RESET = 0x004
} error_action_t;
typedef struct router_object {
ROUTER *(*createInstance)(SERVICE *service, char **options);
void *(*newSession)(ROUTER *instance, SESSION *session);

5
server/modules/protocol/mysql_backend.c
View File

@ -357,8 +357,7 @@ static int gw_read_backend_event(DCB *dcb) {
dcb->delayq,
GWBUF_LENGTH(dcb->delayq))) != NULL);
}
spinlock_release(&dcb->delayqlock);
spinlock_release(&dcb->delayqlock);
{
GWBUF* errbuf;
bool succp;
@ -1464,7 +1463,7 @@ static int gw_change_user(
rv = 0;
goto retblock;
}
/** Set flags that help router to identify session commans reply */
/** Set flags that help router to identify session commands reply */
gwbuf_set_type(buf, GWBUF_TYPE_MYSQL);
gwbuf_set_type(buf, GWBUF_TYPE_SESCMD_RESPONSE);
gwbuf_set_type(buf, GWBUF_TYPE_RESPONSE_END);

25
server/modules/protocol/mysql_client.c
View File

@ -865,7 +865,7 @@ int gw_read_client_event(
rc = SESSION_ROUTE_QUERY(session, read_buffer);
}
/** succeed */
/** Routing succeed */
if (rc)
{
rc = 0; /**< here '0' means success */
@ -874,25 +874,6 @@ int gw_read_client_event(
{
bool succp;
GWBUF* errbuf;
/**
* Create error to be sent to client if session
* can't be continued.
*/
errbuf = mysql_create_custom_error(
1,
0,
"Routing query to backend failed. See "
"the error log for further details.");
router->handleError(
router_instance,
session->router_session,
errbuf,
dcb,
ERRACT_REPLY_CLIENT,
&succp);
free(errbuf);
/**
* Create error to be sent to client if session
* can't be continued.
@ -903,10 +884,10 @@ int gw_read_client_event(
"Routing failed. Session is closed.");
/**
* Ensure that there are enough backends
* available.
* available.
*/
router->handleError(
router_instance,
router_instance,
session->router_session,
errbuf,
dcb,

28
server/modules/routing/readwritesplit/readwritesplit.c
View File

@ -1972,7 +1972,16 @@ retblock:
}
/**
* Routing function. Find out query type, backend type, and target DCB(s).
* Then route query to found target(s).
* @param inst router instance
* @param rses router session
* @param querybuf GWBUF including the query
*
* @return true if routing succeed or if it failed due to unsupported query.
* false if backend failure was encountered.
*/
static bool route_single_stmt(
ROUTER_INSTANCE* inst,
ROUTER_CLIENT_SES* rses,
@ -2162,6 +2171,8 @@ static bool route_single_stmt(
if (TARGET_IS_MASTER(route_target) ||
TARGET_IS_SLAVE(route_target))
{
backend_ref_t* bref = rses->rses_backend_ref;
char* query_str = modutil_get_query(querybuf);
char* qtype_str = skygw_get_qtype_str(qtype);
@ -2181,9 +2192,22 @@ static bool route_single_stmt(
"modification from other "
"servers. <")));
while (bref != NULL && !BREF_IS_IN_USE(bref))
{
bref++;
}
if (bref != NULL && BREF_IS_IN_USE(bref))
{
modutil_reply_parse_error(
bref->bref_dcb,
strdup("Routing query to backend failed. "
"See the error log for further "
"details."));
}
if (query_str) free (query_str);
if (qtype_str) free(qtype_str);
succp = false;
succp = true;
goto retblock;
}
/**