Bug #8880 Commands out of sync error with cursors
Submitted: 2 Mar 2005 10:56 Modified: 12 Apr 2005 2:49
Reporter: Georg Richter Email Updates:
Status: Closed Impact on me:
None 
Category:MySQL Server Severity:S1 (Critical)
Version:5.0.3 OS:Linux (Linux)
Assigned to: Konstantin Osipov CPU Architecture:Any

[2 Mar 2005 10:56] Georg Richter
Description:
When opening two cursors mysql_stmt_execute reports an "Commands out of sync".
See how to repeat.

Note: the sample works as expected if you add more than one row in tables t1.

How to repeat:
#include <stdio.h>
#include <stdlib.h>
#include <mysql.h>

MYSQL_STMT *stmt1, *stmt2;
MYSQL *mysql;

void die_if(int rc, int line, const char *msg) {
	if (rc) {
		printf("Error in line %d: %s\n", line, msg);
		exit (-1);
	}
}

MYSQL_STMT *open_cursor(char *query) {
	const unsigned long type = CURSOR_TYPE_READ_ONLY;

	MYSQL *stmt =  mysql_stmt_init(mysql);
	die_if(mysql_stmt_prepare(stmt, query, strlen(query)), __LINE__, mysql_stmt_error(stmt));
	die_if(mysql_stmt_attr_set(stmt, STMT_ATTR_CURSOR_TYPE, (const void *)&type), __LINE__, mysql_stmt_error(stmt));
	return stmt;
}

int main (int argc, char **argv) {
int rc;
	mysql = mysql_init(NULL);
	mysql_real_connect(mysql, "localhost", "root", "", "test", 0, NULL, 0);

	mysql_query(mysql, "DROP TABLE IF EXISTS t1");
	mysql_query(mysql, "CREATE TABLE t1 (a int not null primary key, b int)");
	mysql_query(mysql, "INSERT INTO t1 VALUES (1,1)");
	/*
	when inserting 2 rows everything works well
	mysql_query(mysql, "INSERT INTO t1 VALUES (1,1),(2,2)");
	*/

	mysql_query(mysql, "DROP TABLE IF EXISTS t2");
	mysql_query(mysql, "CREATE TABLE t2 (a int not null primary key, b int)");
	mysql_query(mysql, "INSERT INTO t2 VALUES (2,2)");

	stmt1 = open_cursor("SELECT a FROM t1");
	stmt2 = open_cursor("SELECT a FROM t2");

	die_if(mysql_stmt_execute(stmt1), __LINE__, mysql_stmt_error(stmt1));
	die_if(mysql_stmt_execute(stmt2), __LINE__, mysql_stmt_error(stmt2));

	mysql_stmt_close(stmt1);
	mysql_stmt_close(stmt2);

	mysql_close(mysql);
}
[23 Mar 2005 15:26] Konstantin Osipov
Subject: bk commit - 5.0 tree (konstantin:1.1829) BUG#9159

ChangeSet
  1.1829 05/03/23 18:01:03 konstantin@mysql.com +5 -0
  Fixes and test cases for Bug#8880 "Commands out of sync error with cursors"
   and Bug#9159 "Server crash during mysql_stmt_close".
  The patch adds support for single-row result sets in cursors.
[24 Mar 2005 14:12] Konstantin Osipov
Pushed into 5.0 tree, which is tagged 5.0.3 (but will go to 5.0.4 most probably).
[12 Apr 2005 2:49] Paul Dubois
Noted in 5.0.4 changelog.