unicode + multithreaded = crash
MySQL Server 4.1.1 alpha
MyODBC Connector: 3.51.08
Hello all,
I am experiencing the following problem: I have an dialog-based MFC app using the
CDatabase class to connect to a MySQL DB using ODBC. My connection string specifies a
DSN with the connection information. Additionally, this is a Unicode compilation (
Project Properties > General > Use Unicode Character Set ). My test app has a
CWinThread-derived class named CDBThread, with a CDatabase member.
CDBThread::InitInstance() calls OpenEx() for the CDatabase member. So far so good.
For the app's InitInstance, all I do is call AfxBeginThread() twice, to create two
threads of type CDBThread. The application crashes when the db thread tries to connect
to the db.
However, there are two things I can do to avoid the crash:
- Start only ONE CDBThread instead of TWO.
- Compile using multi-byte character set instead of Unicode.
Of course, these are both unnaceptable solutions. But it seems the problem is related
only to multi-threaded apps using Unicode. Each CDBThread has its own CDatabase
object, so no additional synchronization should be needed as two separate db
connections should be created, right?
Oh, yeah, I tried replacing the MySQL db with an MS Access db and the problem went
away. Any ideas? Is this a bug?
Here's the stack at the time of the crash:
odbc32.dll!1f7b7e08()
odbc32.dll!1f7b8cd1()
odbc32.dll!1f7c59b8()
odbc32.dll!1f7a2f84()
odbc32.dll!1f7a2cb8()
msvcrt.dll!___updatetlocinfo() + 0x40
[EMAIL PROTECTED]() + 0x67
[EMAIL PROTECTED]() + 0xb
[EMAIL PROTECTED]() + 0xa
[EMAIL PROTECTED]() + 0x2bf
[EMAIL PROTECTED]() + 0x1a250
[EMAIL PROTECTED]() + 0x8f4
[EMAIL PROTECTED]() + 0x144
[EMAIL PROTECTED]() + 0x3c
> mfc71ud.dll!CWnd::GetActiveWindow() Line 193 + 0xf C++
// From my db thread class:
BOOL CDBThread::InitInstance()
{
m_db.OpenEx( _T( "ODBC;DRIVER=MySQL ODBC 3.51 Driver;DSN=dbtest;" ) );
return TRUE;
}
// From the main app:
BOOL CDbtestApp::InitInstance()
{
// (...) MFC wizard stuff here
m_Thread[ 0 ] = AfxBeginThread( RUNTIME_CLASS( CDBThread ) );
m_Thread[ 1 ] = AfxBeginThread( RUNTIME_CLASS( CDBThread ) ); // Comment this
out = no crash
// (...) more MFC wizard stuff here
}
Thank you,
Silvio Lopes de Oliveira
Software Engineer
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OS X Version < 4.1 Multithreaded?
I've heard some recent rumblings that MySQL before 4.1 wasn't multithreaded on OS X. However, in actual usage I see every indication that is IS. Does anyone have a definitive answer either way? Thanks! - John -- --- John May : President <http://www.pointinspace.com> Point In Space Internet Solutions [EMAIL PROTECTED] LPA Corporate Partner / FSA Associate / ACN Member Professional Lasso / PHP / MySQL / FileMaker Pro Hosting -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: Multithreaded?
On Tue, Oct 21, 2003 at 10:13:55AM -0700, Greg(Bear) Casad wrote: > > All installations of mysql I have run ps -fax will show about 5 > mysql proccess running, even at idle. mysql or mysqld? > I compiled on a Redhat 9 box, it did find pthreads however ps > -fax show 1 mysqld process running. Is it using NTPL? > Is there a spot to configure spare proccess? -- Or verify that it is > indeed compiled muli-threaded?? The MySQL server (mysqld) is *always* multi-threaded. As far as "spares", you might want to look at setting your thread_cache to a non-zero value. Jeremy -- Jeremy D. Zawodny | Perl, Web, MySQL, Linux Magazine, Yahoo! <[EMAIL PROTECTED]> | http://jeremy.zawodny.com/ MySQL 4.0.15-Yahoo-SMP: up 39 days, processed 1,493,368,938 queries (439/sec. avg) -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: Multithreaded?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On Tue, 21 Oct 2003, Greg(Bear) Casad wrote: > All installations of mysql I have run ps -fax will show about 5 mysql > proccess running, even at idle. Yep. > I compiled on a Redhat 9 box, it did find pthreads however ps -fax > show 1 mysqld process running. NPTL (RedHat9 comes with NPTL, among other differences between NPTL and old Linuxthreads was this that the threads show as a single process now). http://people.redhat.com/drepper/nptl-design.pdf (btw, can you get a working mysql 4.0.x statically compiled mysqld version on RedHat9 ? I have problems with statically linked programms on NPTL enabled glibc, including mysql. Please compile a 4.0.x version, run it and try to just enter a session with mysql CLI and exit the session and check if the mysqld has crashed/restarted on your exit, check the uptime by "status" command" thanks!) > Is there a spot to configure spare proccess? -- Or verify that it is > indeed compiled muli-threaded?? > I dont know, Im very curious about that too... - Mihai RUSUEmail: [EMAIL PROTECTED] GPG : http://dizzy.roedu.net/dizzy-gpg.txtWWW: http://dizzy.roedu.net "Linux is obsolete" -- AST -BEGIN PGP SIGNATURE- Version: GnuPG v1.2.3 (GNU/Linux) iD8DBQE/lXWpPZzOzrZY/1QRAoaVAKCmY9lS2sho+m4Qov46HyF38ef5NgCgzOs/ lVFCmBm75xAqgpwTJd0nD5c= =hItY -END PGP SIGNATURE- -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
RE: Multithreaded?
On red hat systems threads show up in a normal processlist. Thoese are threads that your seeing, some for connections others to do some innodb tasks and/or replication. - Dathan Vance Pattishall - Sr. Programmer and mySQL DBA for FriendFinder Inc. - http://friendfinder.com/go/p40688 -->-Original Message- -->From: Greg(Bear) Casad [mailto:[EMAIL PROTECTED] -->Sent: Tuesday, October 21, 2003 10:14 AM -->To: [EMAIL PROTECTED] -->Subject: Multithreaded? --> -->All installations of mysql I have run ps -fax will show about 5 mysql -->proccess running, even at idle. -->I compiled on a Redhat 9 box, it did find pthreads however ps -fax -->show 1 mysqld process running. -->Is there a spot to configure spare proccess? -- Or verify that it is -->indeed compiled muli-threaded?? -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Multithreaded?
All installations of mysql I have run ps -fax will show about 5 mysql proccess running, even at idle. I compiled on a Redhat 9 box, it did find pthreads however ps -fax show 1 mysqld process running. Is there a spot to configure spare proccess? -- Or verify that it is indeed compiled muli-threaded??
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I'm using mysql-3.23.29-gamma on Solaris 2.6 sparc. I have a multithreaded mysql client that is linked to libmysqlclient_r. On startup, it dumps core after mysql_init() is called. More specifically, the fault is during the getservbyname() call in mysql_once_init(), which is part of libmysql.c. The core dump only happens if /etc/nsswitch.conf specifies: services: files nis and /etc/inet/services does not contain: mysql 3306/tcp It happens during the search of the NIS services map for the mysql service. I can't tell if it's due to a bug in the /usr/lib/nss_nis.so.1 library or something wrong with the way that the function is invoked. If anyone else is running into this problem, the workaround is either to fix /etc/nsswitch.conf or /etc/inet/services. Has anyone seen this problem? I haven't seen the mysql service name documented anywhere. Should it be? -- -Gary Mills--Unix Support--U of M Academic Computing and Networking- - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
