You need to read up on shared memory. You can't share
pointers between processes and expect them to have any
meaning -- they're addresses from the memory space of
the creating process. You can put them in the shared
memory segment. But they'll just refer to meaningless
memory addresses in another process.
----
Steve Sapovits
GSI Commerce
[EMAIL PROTECTED]
> -----Original Message-----
> From: James Maes [SMTP:[EMAIL PROTECTED]]
> Sent: Wednesday, September 25, 2002 3:01 PM
> To: DBI Mailing List
> Subject: Sharing a DBH via IPC::Shareable.
>
> Hey all, got a problem here which I don't quite understand. I need to
> share a pool of dbi connections between N perl processes. I know that
> only
> one process may use a DBH at at time, and can handle that. The problem
> that
> I am having can been seen in the code below. If I just start up a
> connection, place it in a segment and then try to attach to that segment
> from another process and use the DBH I get the following error.
>
> "dbih_getcom handle DBI::db=HASH(0x828e438) is not a DBI handle (has no
> magic) at ./connection_pool_client.pl line 59."
>
>
> Any idea why a dbh can not be shared via shared memory? What is trying a
> dbh to its original process? What's magic?
>
> Thanks all.
>
>
> Here is my code
>
> connection_pool.pl
> ============================
> #!/usr/bin/perl
>
> ##########################################################################
> ##
> ######
> ## File: connection_pool
> ##
> ## Des:
> ##
> ## Author: James Maes
> ##
> ## Notes:
> ##
> ## Todo:
> ##
> ## Bugs:
> ##
> ## Date: Wed Sep 25 2002
> ##
> ## Version: $Revision$
> ##
> ##########################################################################
> ##
> ######
>
> use DBI;
> use IPC::Shareable (':lock');
>
> ###########################################
> ## setup the needed global semaphore var ##
> ###########################################
> %IPC_INIT_OPTIONS =
> (
> create => 'yes',
> exclusive => 0,
> mode => 0777,
> destroy => 'yes',
> );
>
> $STAT_FILES_GLUE = "SFDS";
>
> ################################################################
> ## use IPC::Shareable to put shared hashes into shared memory ##
> ################################################################
> print "Initializing shared memeory pool\n";
> my $sharedMem;
> tie $sharedMem, 'IPC::Shareable', $STAT_FILES_GLUE, { %IPC_INIT_OPTIONS }
> or
> die("tie write failed.");
>
> ##########################################################################
> ## place the connection in a share memory segment to allow access to it ##
> ##########################################################################
> print "Initializing database connections\n";
> $dbh =
> DBI->connect("dbi:Informix:usermgr\@mldbtcp",,,{AutoCommit=>0,PrintError=>
> 1}
> ) || print "Error : $!\n";
> $sharedMem->{dbh} = $dbh;
> $sharedMem->{name} = "db_connection";
> $sharedMem->{time} = time();
>
>
> print "Done\n";
>
> ####################################
> ## make the stdout filehandle hot ##
> ####################################
> while(1)
> {
> print " . \n";
> sleep(10);
> }
>
>
>
>
> connection_pool_client.pl
> ============================
> #!/usr/bin/perl
>
> ##########################################################################
> ##
> ######
> ## File: connection_pool_client.pl
> ##
> ## Des:
> ##
> ## Author: James Maes
> ##
> ## Notes:
> ##
> ## Todo:
> ##
> ## Bugs:
> ##
> ## Date: Wed Sep 25 2002
> ##
> ## Version: $Revision$
> ##
> ##########################################################################
> ##
> ######
>
> use DBI;
> use INFOplus::DB;
> use IPC::Shareable (':lock');
>
> require "/usr/lib/perl5/5.6.0/dumpvar.pl";
>
> ###########################################
> ## setup the needed global semaphore var ##
> ###########################################
> %IPC_READ_OPTIONS =
> (
> create => 0,
> exclusive => 0,
> mode => 0777,
> destroy => 0,
> );
>
> $STAT_FILES_GLUE = "SFDS";
>
>
> ############################################################
> ## get the stat file hash from the IPC::Shareable segment ##
> ############################################################
> my $sharedMem;
> tie $sharedMem, 'IPC::Shareable', $STAT_FILES_GLUE, { %IPC_READ_OPTIONS }
> or
> die("tie read failed.");
>
> print "Values\n";
> print "dbh = $sharedMem->{dbh}\n";
> print "name = $sharedMem->{name}\n";
> print "time = $sharedMem->{time}\n";
> ## main::dumpValue($sharedMem);
>
>
> $dbh = $sharedMem->{dbh};
>
> print "DBH\n";
> ## main::dumpValue($dbh);
> $dbh->commit();
>
>
> print "Connection\n";
