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.
