Kyle George wrote:
Not exactly related, but there's also a bug I've experienced on 3.9 with
DBD::mysql. See: http://rt.cpan.org/Public/Bug/Display.html?id=20868
I have probably found that bug and I'm waiting for a fix from a guy at
mysql. Here it is the last email from him.
Bye.
-------- Original Message --------
Subject: Re: Memory access problem with DBI or DBD-Mysql?
Date: Mon, 04 Sep 2006 11:04:52 -0400
From: Patrick Galbraith <[EMAIL PROTECTED]>
To: Federico Giannici <[EMAIL PROTECTED]>
CC: dbi-users@perl.org, [EMAIL PROTECTED], Sam Smith <[EMAIL PROTECTED]>
References: <[EMAIL PROTECTED]> <[EMAIL PROTECTED]>
Federico,
That may be the issue. I have encountered this issue in other parts of
the driver. There is a better way to do this, and I can look at making
sure what is being passed is the same data object.
Thanks!
Patrick
Federico Giannici wrote:
> Since there has been no reply to my previous message, I have done
> further investigations trying to find the problem.
>
> Please note that my knowledge of DBI/DBD is almost null, so the
> followings are only simple suppositions.
>
> I have seen that mysql_st_internal_execute() function is executed by
> both the "do" and "execute" methods. It seems that the problems are
> only with the "do" method and not with the "execute", so I looked for
> the differences between them.
>
> The main difference seems to be that "execute" passes a STATEMENT
> handle as first argument, while "do" passes a DATABASE handle. The
> mysql_st_internal_execute() function uses this handle to obtain the
> sth and then from this one the dbh.
>
> So, my hypothesis is that if the initial handle is a database one, the
> sth (and the derived dbh) obtained from this is not a valid one!
>
> Anybody can confirm (or negate) this wild hypothesis?
>
> Thanks.
>
> P.S.
> I want to repeat that the problem manifest itself only under OpenBSD
> because of it's memory management that cause the program to segfault
> if try to access a non allocated memory. In other operating systems, a
> random value is get for "imp_dbh->bind_type_guessing", which is almost
> irrelevant.
>
>
> Federico Giannici wrote:
>
>> It seems to me that there is some kind of memory access problem with
>> DBI or DBD-Mysql.
>>
>> I'm using OpenBSD 3.9-stable amd64. On OpenBSD 3.3 i386 the problem
>> didn't appeared. As you may know, recent version of OpenBSD have a
>> new kind of memory handling that make the programs segfault when they
>> try to access no (longer) allocated memory.
>>
>> I'm using DBI 1.45 and DBD-Mysql 2.9008. I tried DBI 1.52 and
>> DBD-Mysql 3.0006, but the problems were more frequent, so I remained
>> to the old versions.
>>
>> Here is the problem: frequently some "do" commands cause perl to
>> crash with signal 11. The crashes seems to depend on a lot of
>> factors. For example, loading more libraries could make the program
>> to start working. I think it depends on the structure of the memory
>> allocated to the program.
>>
>> Here is the "bt" output of the core dump:
>>
>> #0 0x000000005260a736 in mysql_st_internal_execute (h=0x4713b6e0,
>> statement=0x479b7140, attribs=0x4aa5fd40, numParams=0, params=0x0,
>> cdaPtr=0x7f7ffffc8610, svsock=0x43c90498, use_mysql_use_result=0)
>> at dbdimp.c:1654
>> #1 0x0000000052612da3 in XS_DBD__mysql__db_do (cv=0x40970b20) at
>> mysql.xs:222
>> #2 0x0000000050ddf07b in XS_DBI_dispatch () from
>> /usr/local/libdata/perl5/site_perl/amd64-openbsd/auto/DBI/DBI.so
>> #3 0x000000004a5a1c47 in Perl_pp_entersub () at
>> /usr/src/gnu/usr.bin/perl/pp_hot.c:2890
>> #4 0x000000004a60899e in Perl_runops_standard () at
>> /usr/src/gnu/usr.bin/perl/run.c:37
>> #5 0x000000004a5f744d in S_run_body (oldscope=1) at
>> /usr/src/gnu/usr.bin/perl/perl.c:1936
>> #6 0x000000004a5f7231 in perl_run (my_perl=0x45356258) at
>> /usr/src/gnu/usr.bin/perl/perl.c:1855
>> #7 0x0000000000401afe in main ()
>>
>> I have found the problem is caused by accessing
>> "imp_dbh->bind_type_guessing" for the call to ParseParam() inside
>> mysql_st_internal_execute().
>>
>> I have verified that "imp_dbh" is NOT null, but trying to access any
>> member make the program segfault. So maybe the pointer is a stale one?
>>
>> I have not enough knowledge of DBI to make more debugging.
>>
>>
>> Bye.
>>
>
>
--
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|- [EMAIL PROTECTED]
|ederico Giannici http://www.neomedia.it
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