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Fix for CONC-659:

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When checking for a semi sync indication header, we need also check if
the undocumented session variable @rpl_semi_sync_slave was set.
Otherwise the timestamp of the event could contain values which match
the 2 bytes of the semi sync header.

Since the variable rpl_semi_sync_slave and it's behavior is not documented,
a new option MARIADB_RPL_SEMI_SYNC was added.
This commit is contained in:
Georg Richter
2023-08-11 10:14:26 +02:00
parent cd59c70ce7
commit c8ca89112e
5 changed files with 105 additions and 25 deletions
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115
libmariadb/mariadb_rpl.c
View File

@@ -33,6 +33,8 @@
#ifdef WIN32
#include <malloc.h>
#undef alloca
#define alloca _malloca
#endif
#define RPL_EVENT_HEADER_SIZE 19
@@ -690,9 +692,9 @@ MARIADB_RPL * STDCALL mariadb_rpl_init_ex(MYSQL *mysql, unsigned int version)
if ((rpl->mysql= mysql))
{
MYSQL_RES *result;
if (!mysql_query(mysql, "select @@binlog_checksum"))
{
MYSQL_RES *result;
if ((result= mysql_store_result(mysql)))
{
MYSQL_ROW row= mysql_fetch_row(result);
@@ -795,6 +797,35 @@ int STDCALL mariadb_rpl_open(MARIADB_RPL *rpl)
uint32_t replica_id= rpl->server_id;
ptr= buf= (unsigned char *)alloca(rpl->filename_length + 11);
if (!ptr)
{
rpl_set_error(rpl, CR_OUT_OF_MEMORY, 0);
}
if (rpl->is_semi_sync)
{
if (mysql_query(rpl->mysql, "SET @rpl_semi_sync_slave=1"))
{
rpl_set_error(rpl, mysql_errno(rpl->mysql), 0, mysql_error(rpl->mysql));
return 1;
}
}
else {
MYSQL_RES* result;
MYSQL_ROW row;
if (mysql_query(rpl->mysql, "SELECT @rpl_semi_sync_slave=1"))
{
rpl_set_error(rpl, mysql_errno(rpl->mysql), 0, mysql_error(rpl->mysql));
return 1;
}
if ((result = mysql_store_result(rpl->mysql)))
{
if ((row = mysql_fetch_row(result)))
rpl->is_semi_sync = (row[0] != NULL && row[0][0] == '1');
mysql_free_result(result);
}
}
int4store(ptr, (unsigned int)rpl->start_position);
ptr+= 4;
int2store(ptr, rpl->flags);
@@ -812,6 +843,9 @@ int STDCALL mariadb_rpl_open(MARIADB_RPL *rpl)
char *buf[RPL_BINLOG_MAGIC_SIZE];
MYSQL mysql;
/* Semi sync doesn't work when processing files */
rpl->is_semi_sync = 0;
if (rpl->fp)
ma_close(rpl->fp);
@@ -909,6 +943,50 @@ static uint32_t get_compression_info(const unsigned char *buf,
return len;
}
static uint8_t mariadb_rpl_send_semisync_ack(MARIADB_RPL* rpl, MARIADB_RPL_EVENT* event)
{
size_t buf_size = 0;
uchar* buf;
if (!rpl)
return 1;
if (!event)
{
rpl_set_error(rpl, CR_BINLOG_SEMI_SYNC_ERROR, 0, "Invalid event");
return 1;
}
if (!rpl->is_semi_sync)
{
rpl_set_error(rpl, CR_BINLOG_SEMI_SYNC_ERROR, 0, "semi synchronous replication is not enabled");
return 1;
}
if (!event->is_semi_sync || !event->semi_sync_flags != SEMI_SYNC_ACK_REQ)
{
rpl_set_error(rpl, CR_BINLOG_SEMI_SYNC_ERROR, 0, "This event doesn't require to send semi synchronous acknoledgement");
return 1;
}
buf_size = rpl->filename_length + 9;
buf = alloca(buf_size);
buf[0] = SEMI_SYNC_INDICATOR;
int8store(buf + 1, event->next_event_pos);
memcpy(buf + 9, rpl->filename, rpl->filename_length);
ma_net_clear(&rpl->mysql->net);
if (ma_net_write(&rpl->mysql->net, buf, buf_size) ||
(ma_net_flush(&rpl->mysql->net)))
{
rpl_set_error(rpl, CR_CONNECTION_ERROR, 0);
return 1;
}
return 0;
}
MARIADB_RPL_EVENT * STDCALL mariadb_rpl_fetch(MARIADB_RPL *rpl, MARIADB_RPL_EVENT *event)
{
unsigned char *ev= 0;
@@ -1032,7 +1110,7 @@ MARIADB_RPL_EVENT * STDCALL mariadb_rpl_fetch(MARIADB_RPL *rpl, MARIADB_RPL_EVEN
rpl_event->ok= *ev++;
/* CONC-470: add support for semi snychronous replication */
if ((rpl_event->is_semi_sync= (*ev == SEMI_SYNC_INDICATOR)))
if (rpl->is_semi_sync && (rpl_event->is_semi_sync= (*ev == SEMI_SYNC_INDICATOR)))
{
RPL_CHECK_POS(ev, ev_end, 1);
ev++;
@@ -1826,19 +1904,11 @@ MARIADB_RPL_EVENT * STDCALL mariadb_rpl_fetch(MARIADB_RPL *rpl, MARIADB_RPL_EVEN
if (rpl_event->is_semi_sync &&
rpl_event->semi_sync_flags == SEMI_SYNC_ACK_REQ)
{
size_t buf_size= rpl->filename_length + 1 + 8;
uchar *buffer= alloca(buf_size);
buffer[0]= SEMI_SYNC_INDICATOR;
int8store(buffer + 1, (int64_t)rpl_event->next_event_pos);
memcpy(buffer + 9, rpl->filename, rpl->filename_length);
/* clear network buffer before sending the reply packet*/
ma_net_clear(&rpl->mysql->net);
if (ma_net_write(&rpl->mysql->net, buffer, buf_size) ||
(ma_net_flush(&rpl->mysql->net)))
goto net_error;
if (mariadb_rpl_send_semisync_ack(rpl, rpl_event))
{
/* ACK failed and rpl->error was set */
return rpl_event;
}
}
if (rpl->use_checksum && !rpl_event->checksum)
@@ -1865,10 +1935,6 @@ mem_error:
mariadb_free_rpl_event(rpl_event);
rpl_set_error(rpl, CR_OUT_OF_MEMORY, 0);
return 0;
net_error:
mariadb_free_rpl_event(rpl_event);
rpl_set_error(rpl, CR_CONNECTION_ERROR, 0);
return 0;
malformed_packet:
rpl_set_error(rpl, CR_BINLOG_ERROR, 0, RPL_ERR_POS(rpl),
"Malformed packet");
@@ -1961,6 +2027,11 @@ int STDCALL mariadb_rpl_optionsv(MARIADB_RPL *rpl,
rpl->extract_values= (uint8_t)va_arg(ap, uint32_t);
break;
}
case MARIADB_RPL_SEMI_SYNC:
{
rpl->is_semi_sync = (uint8_t)va_arg(ap, uint32_t);
break;
}
default:
rc= -1;
goto end;
@@ -2009,6 +2080,12 @@ int STDCALL mariadb_rpl_get_optionsv(MARIADB_RPL *rpl,
*start= rpl->start_position;
break;
}
case MARIADB_RPL_SEMI_SYNC:
{
unsigned int* semi_sync = va_arg(ap, unsigned int*);
*semi_sync = rpl->is_semi_sync;
}
default:
va_end(ap);
return 1;