maria-developers team mailing list archive

[Sergey Vojtovich <svoj@xxxxxxxxxxx>]

Hi Kentoku,

On Wed, Sep 25, 2013 at 02:53:17AM +0900, kentoku wrote:
> Hi Sergey,
> 
> > The above should have been fixed back in the beginning of 2012. Which
> MariaDB
> revision are you testing with?
> It's same as lp:~kentokushiba/maria/10.0.4-spider-3.0.
That's very strange. How did you build it and what command line options did
you use (including those that are listed in my.cnf)?

> By the way, I found a problem point in Spider. Currently it is fixed and
> pushed. And I can't reproduce assertion failure. Can you reproduce this
> failure yet?
I just tested 10.0.4-spider-3.0 with rev.3827, it still fails.

Regards,
Sergey

> 
> Thanks,
> Kentoku
> 
> 
> 
> 
> 2013/9/24 Sergey Vojtovich <svoj@xxxxxxxxxxx>
> 
> > Hi Kentoku,
> >
> > On Thu, Sep 19, 2013 at 11:47:33PM +0900, kentoku wrote:
> > > Hi Sergey,
> > >
> > > > I'm afraid fixing rnd_end() callers in the server may stall for a long
> > > time.
> > > O.K. No need to fix it if it is not easy. This request is not high
> > priority
> > > request.
> > >
> > > > Is it accaptable for spider to use bulk updates and deletes API instead
> > > > (see handler.h: start_bulk_update/start_bulk_delete).
> > > Spider use it already. This API is not used if target table has after
> > > trigger. I understand why this API is not used in this case, but it
> > > sometimes causes performance problem. So, I thought it is better to
> > prepare
> > > other choice for something wrong. Anyway, I will disable bulk
> > > updating/deleting feature without using API.
> > I see. Hope it is acceptable.
> >
> > >
> > > > Nope, it looks like a bug in thread pool. MDEV-4739 has different
> > trace,
> > > how
> > > did you get this one? Just executed given test?
> > > I got this trace when I try to reproduce MDEV-4739. I did as the
> > followings.
> > >
> > > 1. start mysqld
> > > 2. log in mysqld
> > > 3. mysql> CREATE TABLE t1 (a INT) ENGINE=InnoDB;
> > > 4. mysql> XA START 'xa1';
> > > 5. mysql> INSERT INTO t1 (a) VALUES (1),(2);
> > > 6. mysql> XA END 'xa1';
> > > 7. mysql> XA PREPARE 'xa1';
> > > 8. kill -9 mysqld_safe and mysqld from another terminal
> > > 9. start mysqld on gdb
> > >
> > > At that time, InnoDB and Spider were enabled and log-bin was disabled. So
> > > probably "total_ha_2pc > 1" was true, "opt_bin_log" was false.
> > > Does it help you?
> > We couldn't reproduce it yet. :(
> >
> > Looking through the code I noticed that call to thd_wait_begin() looks as
> > following:
> >
> > static void scheduler_wait_sync_begin(void) {
> >   thd_wait_begin(NULL, THD_WAIT_SYNC);
> > }
> >
> > Note that thd is always NULL. And it must be NULL at this point, because
> > we're
> > booting. But according to your trace thd is not NULL.
> >
> > #0  0x00000000005eabf6 in thd_wait_begin (
> >     thd=0x29da060, wait_type=10)
> >     at /ssd1/mariadb-10.0.4/sql/sql_class.cc:4277
> > #1  0x000000000072a114 in scheduler_wait_sync_begin ()
> >     at /ssd1/mariadb-10.0.4/sql/scheduler.cc:59
> > ...
> >
> > The above should have been fixed back in the beginning of 2012. Which
> > MariaDB
> > revision are you testing with?
> >
> > Thanks,
> > Sergey
> >
> >
> >
> > >
> > > Thanks,
> > > Kentoku
> > >
> > >
> > >
> > > 2013/9/19 Sergey Vojtovich <svoj@xxxxxxxxxxx>
> > >
> > > > Hi Kentoku,
> > > >
> > > > I'm adding MariaDB developers to CC.
> > > >
> > > > On Thu, Sep 19, 2013 at 01:19:13AM +0900, kentoku wrote:
> > > > > Hi Sergey,
> > > > >
> > > > > > But what kind of errors are possible in your case? Other storage
> > > > engines
> > > > > doesn't
> > > > > seem to suffer from this API violation.
> > > > >
> > > > > Spider support bulk updating and deleting for avoiding network
> > roundtrip
> > > > > between data node. Some times, last bulk updating is executed in
> > > > rnd_end()
> > > > > function. So rnd_end() has possibility getting errors from data node.
> > > > I'm afraid fixing rnd_end() callers in the server may stall for a long
> > > > time.
> > > > Is it accaptable for spider to use bulk updates and deletes API instead
> > > > (see handler.h: start_bulk_update/start_bulk_delete).
> > > >
> > > > > By the way, about MDEV-4739. I get the following stack trace.
> > > > > Program received signal SIGSEGV, Segmentation fault.
> > > > > 0x00000000005eabf6 in thd_wait_begin (thd=0x29da060,
> > > > >     wait_type=10)
> > > > >     at /ssd1/mariadb-10.0.4/sql/sql_class.cc:4277
> > > > > 4277      MYSQL_CALLBACK(thd->scheduler, thd_wait_begin, (thd,
> > > > wait_type));
> > > > > (gdb) print thd
> > > > > $1 = (THD *) 0x29da060
> > > > > (gdb) bt
> > > > > #0  0x00000000005eabf6 in thd_wait_begin (
> > > > >     thd=0x29da060, wait_type=10)
> > > > >     at /ssd1/mariadb-10.0.4/sql/sql_class.cc:4277
> > > > > #1  0x000000000072a114 in scheduler_wait_sync_begin ()
> > > > >     at /ssd1/mariadb-10.0.4/sql/scheduler.cc:59
> > > > > #2  0x0000000000d6dc20 in my_sync (fd=23, my_flags=0)
> > > > >     at /ssd1/mariadb-10.0.4/mysys/my_sync.c:76
> > > > > #3  0x0000000000d6b54f in my_msync (fd=23,
> > > > >     addr=0x7ffff7ff4000, len=4096, flags=4)
> > > > >     at /ssd1/mariadb-10.0.4/mysys/my_mmap.c:27
> > > > > #4  0x00000000008bea03 in TC_LOG_MMAP::open (
> > > > >     this=0x16e6a00, opt_name=0xe19c87 "tc.log")
> > > > >     at /ssd1/mariadb-10.0.4/sql/log.cc:7735
> > > > > #5  0x00000000005751cb in init_server_components ()
> > > > >     at /ssd1/mariadb-10.0.4/sql/mysqld.cc:4797
> > > > > #6  0x0000000000575a07 in mysqld_main (argc=30,
> > > > >     argv=0x1f204d0)
> > > > >     at /ssd1/mariadb-10.0.4/sql/mysqld.cc:5208
> > > > > #7  0x000000000056d884 in main (argc=11,
> > > > >     argv=0x7fffffffe3a8)
> > > > >     at /ssd1/mariadb-10.0.4/sql/main.cc:25
> > > > > (gdb) print thd->scheduler
> > > > > $2 = (scheduler_functions *) 0x8f8f8f8f8f8f8f8f
> > > > > (gdb) print thd_wait_begin
> > > > > $3 = {void (THD *,
> > > > >     int)} 0x5eaba4 <thd_wait_begin(THD*, int)>
> > > > > (gdb) print wait_type
> > > > > $4 = 10
> > > > >
> > > > > It is looks that "thd->scheduler" is not initialized. What do you
> > think?
> > > > > Must storage engine set it?
> > > > Nope, it looks like a bug in thread pool. MDEV-4739 has different
> > trace,
> > > > how
> > > > did you get this one? Just executed given test?
> > > >
> > > > Regards,
> > > > Sergey
> > > >
> >