hcq/MaxScale
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

MXS-1751: Fix crash with available_when_donor=true

Browse Source 
The `MYSQL_ROW row` variable was being overwritten by the extra query done
by the SST method detection code. Moving it into its own function prevents
this and makes the code significantly easier to comprehend.

Added a test case that reproduced the problem (MaxScale crashed) and
verifies that the patch fixes the problem.
This commit is contained in:
Markus Mäkelä
2018-03-29 18:00:12 +03:00
parent b11fb53b95
commit 4167e88719
4 changed files with 128 additions and 28 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
maxscale-system-test/CMakeLists.txt
View File

@ -621,6 +621,10 @@ add_test_executable(mxs1713_lots_of_databases.cpp mxs1713_lots_of_databases mxs1
# https://jira.mariadb.org/browse/MXS-1731
add_test_executable(mxs1731_old_persisted_config.cpp mxs1731_old_persisted_config replication LABELS REPL_BACKEND)
# MXS-1751: Maxscale crashes when certain config is in play (with nodes down)
# https://jira.mariadb.org/browse/MXS-1751
add_test_executable(mxs1751_available_when_donor_crash.cpp mxs1751_available_when_donor_crash mxs1751_available_when_donor_crash LABELS GALERA_BACKEND)
# 'namedserverfilter' test
add_test_executable(namedserverfilter.cpp namedserverfilter namedserverfilter LABELS namedserverfilter LIGHT REPL_BACKEND)

53
maxscale-system-test/cnf/maxscale.cnf.template.mxs1751_available_when_donor_crash Executable file
View File

@ -0,0 +1,53 @@
[maxscale]
threads=###threads###
[Galera Monitor]
type=monitor
module=galeramon
servers=server1,server2,server3
user=maxskysql
passwd=skysql
monitor_interval=100
available_when_donor=true
[RW Split Router]
type=service
router=readwritesplit
servers=server1,server2,server3
user=maxskysql
passwd=skysql
master_accept_reads=true
[RW Split Listener]
type=listener
service=RW Split Router
protocol=MySQLClient
port=4006
[CLI]
type=service
router=cli
[CLI Listener]
type=listener
service=CLI
protocol=maxscaled
socket=default
[server1]
type=server
address=###galera_server_IP_1###
port=###galera_server_port_1###
protocol=MySQLBackend
[server2]
type=server
address=###galera_server_IP_2###
port=###galera_server_port_2###
protocol=MySQLBackend
[server3]
type=server
address=###galera_server_IP_3###
port=###galera_server_port_3###
protocol=MySQLBackend

30
maxscale-system-test/mxs1751_available_when_donor_crash.cpp Normal file
View File

@ -0,0 +1,30 @@
/*
* Copyright (c) 2016 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
*
* Change Date: 2020-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
#include "testconnections.h"
int main(int argc, char* argv[])
{
TestConnections test(argc, argv);
for (int i = 0; i < 2; i++)
{
test.galera->stop_node(0);
test.galera->stop_node(1);
test.galera->start_node(1);
test.galera->start_node(0);
test.galera->fix_replication();
}
return test.global_result;
}

67
server/modules/monitor/galeramon/galeramon.c
View File

@ -260,6 +260,41 @@ static json_t* diagnostics_json(const MXS_MONITOR *mon)
return rval;
}
static bool using_xtrabackup(MXS_MONITORED_SERVER *database, const char* server_string)
{
bool rval = false;
MYSQL_RES* result;
if (mxs_mysql_query(database->con, "SHOW VARIABLES LIKE 'wsrep_sst_method'") == 0
&& (result = mysql_store_result(database->con)) != NULL)
{
if (mysql_field_count(database->con) < 2)
{
mysql_free_result(result);
MXS_ERROR("Unexpected result for \"SHOW VARIABLES LIKE "
"'wsrep_sst_method'\". Expected 2 columns."
" MySQL Version: %s", server_string);
}
MYSQL_ROW row;
while ((row = mysql_fetch_row(result)))
{
if (row[1] && strncmp(row[1], "xtrabackup", 10) == 0)
{
rval = true;
}
}
mysql_free_result(result);
}
else
{
mon_report_query_error(database);
}
return rval;
}
/**
* Monitor an individual server. Does not deal with the setting of master or
* slave bits, except for clearing them when a server is not joined to the
@ -273,8 +308,7 @@ monitorDatabase(MXS_MONITOR *mon, MXS_MONITORED_SERVER *database)
{
GALERA_MONITOR* handle = (GALERA_MONITOR*) mon->handle;
MYSQL_ROW row;
MYSQL_RES *result, *result2;
int isjoined = 0;
MYSQL_RES *result;
char *server_string;
/* Don't even probe server flagged as in maintenance */
@ -364,6 +398,8 @@ monitorDatabase(MXS_MONITOR *mon, MXS_MONITORED_SERVER *database)
info.local_index = local_index;
}
ss_dassert(row[0] && row[1]);
if (strcmp(row[0], "wsrep_local_state") == 0)
{
if (strcmp(row[1], "4") == 0)
@ -371,34 +407,11 @@ monitorDatabase(MXS_MONITOR *mon, MXS_MONITORED_SERVER *database)
info.joined = 1;
}
/* Check if the node is a donor and is using xtrabackup, in this case it can stay alive */
else if (strcmp(row[1], "2") == 0 && handle->availableWhenDonor == 1)
{
if (mxs_mysql_query(database->con, "SHOW VARIABLES LIKE 'wsrep_sst_method'") == 0
&& (result2 = mysql_store_result(database->con)) != NULL)
{
if (mysql_field_count(database->con) < 2)
{
mysql_free_result(result);
mysql_free_result(result2);
MXS_ERROR("Unexpected result for \"SHOW VARIABLES LIKE "
"'wsrep_sst_method'\". Expected 2 columns."
" MySQL Version: %s", server_string);
return;
}
while ((row = mysql_fetch_row(result2)))
{
if (strncmp(row[1], "xtrabackup", 10) == 0)
else if (strcmp(row[1], "2") == 0 && handle->availableWhenDonor == 1 &&
using_xtrabackup(database, server_string))
{
info.joined = 1;
}
}
mysql_free_result(result2);
}
else
{
mon_report_query_error(database);
}
}
else
{
/* Force joined = 0 */