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Message #00179
[Bug 1831872] Re: Long query gets stuck despite max_statement_time being set
** Description changed:
I am on Ubuntu 18, using oursql 0.9.3.2, and /usr/lib/x86_64-linux-
gnu/libmysqlclient.so.20
I am using oursql to connect to 2 different servers: MariaDB 10.1.38 and
MariaDB 10.3.15:
Expected behavior (MariaDB 10.1.38):
conn = oursql.connect(host='maridb-10.1.38', ...)
curs = conn.cursor()
curs.execute("SET SESSION max_statement_time=1")
curs.execute("SHOW variables like 'max_statement_%'")
curs.fetchall()
>> [(u'max_statement_time', u'1.000000')]
curs.execute(long_query)
curs.fetchall()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "oursqlx/cursor.pyx", line 122, in oursql.Cursor.execute (oursqlx/oursql.c:20330)
File "oursqlx/statement.pyx", line 402, in oursql._Statement.execute (oursqlx/oursql.c:13119)
File "oursqlx/statement.pyx", line 127, in oursql._Statement._raise_error (oursqlx/oursql.c:9947)
oursql.UnknownError: (1969, 'Query execution was interrupted (max_statement_time exceeded)', None)
Unexpected behavior (MariaDB 10.3.15):
conn = oursql.connect(host='maridb-10.3.15', ...)
curs = conn.cursor()
curs.execute("SET SESSION max_statement_time=1")
curs.execute("SHOW variables like 'max_statement_%'")
curs.fetchall()
>> [(u'max_statement_time', u'1.000000')]
curs.execute(long_query)
curs.fetchall()
... Gets stuck
- I have 3 interesting observations:
+ I have 2 interesting observations:
- looking at 'processlist' on the server side confirms that the query was actually canceled (connection is in sleep mode)
- running the same sequence using the 'mysql' CLI of MariaDB 10.1.38 against the MariaDB 10.3.15 server works fine (query is interrupted).
- - I've tried the same using the C client (libmysqlclient) and the query times out as expected.
- Any hints as to how to debug this will be highly appreciated. The
- problem seems to be in oursql and not in libmysqlclient.
+ Any hints as to how to debug this will be highly appreciated.
+
+ Below is my C++ program that executes the same using libmysqlclient:
+
+ =====================
+
+ #include <my_global.h>
+ #include <mysql.h>
+
+ #include <iostream>
+ using namespace std;
+
+ int finish_with_error(MYSQL *con)
+ {
+ cerr << mysql_error(con) << endl;
+ mysql_close(con);
+ return 1;
+ }
+
+ int main()
+ {
+ cout << "MySQL client version: " << mysql_get_client_info() << endl;
+
+ MYSQL *con = mysql_init(NULL);
+
+ if (con == NULL)
+ {
+ cerr << "mysqlinit() failed" << endl;
+ return 1;
+ }
+
+ if (mysql_real_connect(con, "maridb-10.3.15", "<user>", "<password>", "<database>", 0, NULL, 0) == NULL)
+ {
+ return finish_with_error(con);
+ }
+
+ if (mysql_query(con, "SET SESSION max_statement_time=1"))
+ {
+ return finish_with_error(con);
+ }
+
+ if (mysql_query(con, "<long running query>"))
+ {
+ return finish_with_error(con);
+ }
+
+ MYSQL_RES *result = mysql_store_result(con);
+ if (result == NULL)
+ {
+ return finish_with_error(con);
+ }
+ mysql_free_result(result);
+
+ mysql_close(con);
+ return 0;
+ }
+
+
+ g++ -o test test.cpp $(mysql_config --cflags --libs)
+ ./test
+
+ MySQL client version: 5.7.26
+ Query execution was interrupted (max_statement_time exceeded)
** Description changed:
I am on Ubuntu 18, using oursql 0.9.3.2, and /usr/lib/x86_64-linux-
gnu/libmysqlclient.so.20
I am using oursql to connect to 2 different servers: MariaDB 10.1.38 and
MariaDB 10.3.15:
Expected behavior (MariaDB 10.1.38):
conn = oursql.connect(host='maridb-10.1.38', ...)
curs = conn.cursor()
curs.execute("SET SESSION max_statement_time=1")
curs.execute("SHOW variables like 'max_statement_%'")
curs.fetchall()
>> [(u'max_statement_time', u'1.000000')]
curs.execute(long_query)
curs.fetchall()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "oursqlx/cursor.pyx", line 122, in oursql.Cursor.execute (oursqlx/oursql.c:20330)
File "oursqlx/statement.pyx", line 402, in oursql._Statement.execute (oursqlx/oursql.c:13119)
File "oursqlx/statement.pyx", line 127, in oursql._Statement._raise_error (oursqlx/oursql.c:9947)
oursql.UnknownError: (1969, 'Query execution was interrupted (max_statement_time exceeded)', None)
Unexpected behavior (MariaDB 10.3.15):
conn = oursql.connect(host='maridb-10.3.15', ...)
curs = conn.cursor()
curs.execute("SET SESSION max_statement_time=1")
curs.execute("SHOW variables like 'max_statement_%'")
curs.fetchall()
>> [(u'max_statement_time', u'1.000000')]
curs.execute(long_query)
curs.fetchall()
... Gets stuck
- I have 2 interesting observations:
+ I have 3 interesting observations:
- looking at 'processlist' on the server side confirms that the query was actually canceled (connection is in sleep mode)
- running the same sequence using the 'mysql' CLI of MariaDB 10.1.38 against the MariaDB 10.3.15 server works fine (query is interrupted).
+ - running the same sequence using libmysqlclient from C code works.
Any hints as to how to debug this will be highly appreciated.
Below is my C++ program that executes the same using libmysqlclient:
=====================
#include <my_global.h>
#include <mysql.h>
#include <iostream>
using namespace std;
int finish_with_error(MYSQL *con)
{
- cerr << mysql_error(con) << endl;
- mysql_close(con);
- return 1;
+ cerr << mysql_error(con) << endl;
+ mysql_close(con);
+ return 1;
}
int main()
{
- cout << "MySQL client version: " << mysql_get_client_info() << endl;
+ cout << "MySQL client version: " << mysql_get_client_info() << endl;
- MYSQL *con = mysql_init(NULL);
+ MYSQL *con = mysql_init(NULL);
- if (con == NULL)
- {
- cerr << "mysqlinit() failed" << endl;
- return 1;
- }
+ if (con == NULL)
+ {
+ cerr << "mysqlinit() failed" << endl;
+ return 1;
+ }
- if (mysql_real_connect(con, "maridb-10.3.15", "<user>", "<password>", "<database>", 0, NULL, 0) == NULL)
- {
- return finish_with_error(con);
- }
+ if (mysql_real_connect(con, "maridb-10.3.15", "<user>", "<password>", "<database>", 0, NULL, 0) == NULL)
+ {
+ return finish_with_error(con);
+ }
- if (mysql_query(con, "SET SESSION max_statement_time=1"))
- {
- return finish_with_error(con);
- }
+ if (mysql_query(con, "SET SESSION max_statement_time=1"))
+ {
+ return finish_with_error(con);
+ }
- if (mysql_query(con, "<long running query>"))
- {
- return finish_with_error(con);
- }
+ if (mysql_query(con, "<long running query>"))
+ {
+ return finish_with_error(con);
+ }
- MYSQL_RES *result = mysql_store_result(con);
- if (result == NULL)
- {
- return finish_with_error(con);
- }
- mysql_free_result(result);
+ MYSQL_RES *result = mysql_store_result(con);
+ if (result == NULL)
+ {
+ return finish_with_error(con);
+ }
+ mysql_free_result(result);
- mysql_close(con);
- return 0;
+ mysql_close(con);
+ return 0;
}
-
g++ -o test test.cpp $(mysql_config --cflags --libs)
./test
MySQL client version: 5.7.26
Query execution was interrupted (max_statement_time exceeded)
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https://bugs.launchpad.net/bugs/1831872
Title:
Long query gets stuck despite max_statement_time being set
Status in oursql:
New
Bug description:
I am on Ubuntu 18, using oursql 0.9.3.2, and /usr/lib/x86_64-linux-
gnu/libmysqlclient.so.20
I am using oursql to connect to 2 different servers: MariaDB 10.1.38
and MariaDB 10.3.15:
Expected behavior (MariaDB 10.1.38):
conn = oursql.connect(host='maridb-10.1.38', ...)
curs = conn.cursor()
curs.execute("SET SESSION max_statement_time=1")
curs.execute("SHOW variables like 'max_statement_%'")
curs.fetchall()
>> [(u'max_statement_time', u'1.000000')]
curs.execute(long_query)
curs.fetchall()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "oursqlx/cursor.pyx", line 122, in oursql.Cursor.execute (oursqlx/oursql.c:20330)
File "oursqlx/statement.pyx", line 402, in oursql._Statement.execute (oursqlx/oursql.c:13119)
File "oursqlx/statement.pyx", line 127, in oursql._Statement._raise_error (oursqlx/oursql.c:9947)
oursql.UnknownError: (1969, 'Query execution was interrupted (max_statement_time exceeded)', None)
Unexpected behavior (MariaDB 10.3.15):
conn = oursql.connect(host='maridb-10.3.15', ...)
curs = conn.cursor()
curs.execute("SET SESSION max_statement_time=1")
curs.execute("SHOW variables like 'max_statement_%'")
curs.fetchall()
>> [(u'max_statement_time', u'1.000000')]
curs.execute(long_query)
curs.fetchall()
... Gets stuck
I have 3 interesting observations:
- looking at 'processlist' on the server side confirms that the query was actually canceled (connection is in sleep mode)
- running the same sequence using the 'mysql' CLI of MariaDB 10.1.38 against the MariaDB 10.3.15 server works fine (query is interrupted).
- running the same sequence using libmysqlclient from C code works.
Any hints as to how to debug this will be highly appreciated.
Below is my C++ program that executes the same using libmysqlclient:
=====================
#include <my_global.h>
#include <mysql.h>
#include <iostream>
using namespace std;
int finish_with_error(MYSQL *con)
{
cerr << mysql_error(con) << endl;
mysql_close(con);
return 1;
}
int main()
{
cout << "MySQL client version: " << mysql_get_client_info() << endl;
MYSQL *con = mysql_init(NULL);
if (con == NULL)
{
cerr << "mysqlinit() failed" << endl;
return 1;
}
if (mysql_real_connect(con, "maridb-10.3.15", "<user>", "<password>", "<database>", 0, NULL, 0) == NULL)
{
return finish_with_error(con);
}
if (mysql_query(con, "SET SESSION max_statement_time=1"))
{
return finish_with_error(con);
}
if (mysql_query(con, "<long running query>"))
{
return finish_with_error(con);
}
MYSQL_RES *result = mysql_store_result(con);
if (result == NULL)
{
return finish_with_error(con);
}
mysql_free_result(result);
mysql_close(con);
return 0;
}
g++ -o test test.cpp $(mysql_config --cflags --libs)
./test
MySQL client version: 5.7.26
Query execution was interrupted (max_statement_time exceeded)
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References
