I have a problem in a perl script that I'm writing. When I run the script it hangs after prepare(). I've tried to run the update statement from SQL Developer and it works fine.
I've also tried to print out all parameters and they are correct.
What am I missing here?
my $upd = 'update ngs.pp_subscr_data set address=?, city=?, postalcode=?, kennitala=?, email=?, firstname=?, lastname=?, last_upd=systimestamp where snb=?';
my $s = $dbh->prepare ($upd) || exitError(-9802, 'Couldn\'t prepare update statement.');
$s->execute($addr, $city, $pcode, $ktala, $email, $fname, $lname, $snb) || exitError(-9803, 'Couldn\'t execute statement: ' . $s->errstr);
Thanks.
First, what version of Oracle?
Ok, I see couple of problems with your description. When you say "hang", is it really a hang? Could it be spinning?
Also, second, you say "... it hangs after prepare()". Does that mean it hangs after you call prepare(), or after it returns from prepare()?
Is it hanging in the database, and your client program is waiting for a database call to complete?
You need to run the program, then look at V$SESSION, identify the SID that corresponds to the database session of your program, and see what it's doing. Look at the EVENT column in V$SESSION. Also, look at the STATUS column to tell if the session is currently in a database call (ACTIVE), or waiting for the client program to call the database (INACTIVE).
Report some information back, and I may be able to provide further insight.
Hope that helps.
Related
I am applying the cicindela2 recommendation engine
It uses Apache mod_perl and the Perl DBI module.
Here is the rough flow of how it works
Data input by Record Handler
Data is passed through the filter chain for batch processing
Temporary tables are output from batch processing
Recommendation result is requested by accessing the Recommend Handler which trigger the action of Recommender
I configured an aggregation and ran the project batch script. I know that the batch processing succeeded because I saw the output of processing from DB. But when I tried to access the recommendation result with URL that triggers the Recommend Handler, I saw a blank white page and the log said
FATAL: Insecure dependency in parameter 1 of DBIx::ContextualFetch::db=HASH(0x7f2a76169e78)->prepare_cached method call while running with -T switch at /usr/local/share/perl5/Ima/DBI.pm line 398.
This is where the error was thrown from the
Ima::DBI
base module
/usr/local/share/perl5/Ima/DBI.pm.
sub _mk_sql_closure {
my ($class, $sql_name, $statement, $db_meth, $cache) = #_;
return sub {
my $class = shift;
my $dbh = $class->$db_meth();
# Everything must pass through sprintf, even if #_ is empty.
# This is to do proper '%%' translation.
my $sql = $class->transform_sql($statement => #_);
return $cache # Line 398
? $dbh->prepare_cached($sql)
: $dbh->prepare($sql);
};
}
It seems that the SQL query prepared by the program is insecure, right?
What is reason for this error?
Is it related to the function of cache management of DBI?
Would it be solved if I clear the cache regularly?
Also, I tried to log the SQL statement generated, but the output failed even when I placed something like $LOGGER->warn("123") in the handle subroutine of the Recommend Handler.
How come the log failed and how to log it correctly?
Insecure dependency... while running with -T switch is Perl's way of telling you that you're running with taint mode active and attempting to do something with tainted data which could be potentially unsafe. In this particular case, $sql is tainted, because some or all of its content came from sources external to the program - probably user input, although it could also have been read from a file.
To fix this, you need to think about where $sql came from, so that you can work out the appropriate way to clean it up.
In the most likely scenario, you've asked a user to supply search terms and then inserted those terms directly into your SQL string. This is a bad idea in general, as it opens you up to the possibility of SQL injection attacks. (Obligatory Bobby Tables link.) Revise your SQL handling to make use of SQL placeholders instead of inserting user input into the WHERE clause and this vulnerability should go away.
If tainted data is making its way into $sql in some other way, you need to clean up the tainted data by using a regular expression to validate it and capture the validated data, then assign the captured data to your variable. e.g.,
my $tainted = <STDIN>;
$tainted =~ /([A-Z]*)/; # Only allow uppercase characters
my $clean = $1; # No longer tainted because it came from $1
If you need to take this route, DO NOT use .* as your regex to untaint the data without serious, serious consideration, because, if you just blindly accept any and all data, you will be discarding any and all benefit provided by taint mode.
I am desperately trying to find an easy way to regulary check if a PGSQL server is still alive from within a perl script. I intended to use pg_ping for this, but in my tests pg_ping always returns 1, independently of the DB server status.
Here's the code I tried it with:
#!/usr/bin/perl
use strict;
use warnings;
use DBD::Pg;
my $dbh=DBI->connect("DBI:Pg:dbname=healthcheck;host=vm0484","healthcheck","areyoustillthere");
for (my $i=1;$i<100;$i++) {
print "$i. pg_ping: ".$dbh->pg_ping."\n";
sleep(1);
}
I then used kill -9 in another window to manually terminate the PGSQL-server, but the result was still 1. Did I do something wrong?
If not, how do I best check, if the DB server is still alive?
Thanks in advance.
You can manually perform query like
select 1 as is_alive
as ping() also claim to do something similar,
The ping method issues an empty query and checks the result status.
So I started to get familiar with Perl and I wrote my first Db script.
Now I am trying to select data from atable which is huge and trying to insert into a summary table based on some criteria.
Now there are chances , that select query may fail or the insert query may fail due to timeout or other database issues that is beyond my control.
Eventually my script is going to be cron script.
Can I log just the errors that i encounter for the connection,inserts and selects into a file generated in the script?
$logfile = $path.'logs/$currdate.log';
here is my code:
my $SQL_handled="SELECT division_id,region_id, NVL(COUNT(*),0) FROM super_tab GROUP BY division_id,region_id;";
my $result_handled = $dbh->prepare($SQL_handled);
$result_handled->execute();
while (my ($division_id,$region_id,$count ) = $result_handled->fetchrow_array()){
my $InsertHandled="INSERT INTO summary_tab (date_hour, division_id, region_id,volume) VALUES ('$current',$division_id,$region_id,$market_id,'$service_type','$handled',$count);";
my $result_insert_handled = $dbh->prepare($InsertHandled);
$result_insert_handled->execute();
}
something like
if(DBI-query failed ) {
// log the error onto the above logpath
}
Its usually done like this
my $SQL_handled="SELECT division_id,region_id, NVL(COUNT(*),0) FROM super_tab GROUP BY division_id,region_id;";
my $result_handled = $dbh->prepare($SQL_handled);
my $retval = $result_handled->execute();
if(!$retval){
#open a log file and write errors
writelog();
die "Error executing SQL SELECT - $dbh->errstr";
}
while(my ($division_id,$region_id,$count ) = $result_handled->fetchrow_array()){....
}
---------------------------------
sub writelog{
my $path = "/path/to/logfile";
my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(time);
$year += 1900;
$mon++;
my $currdate = "$mon$mday$year";
$logfile = $path . "/$currdate.log";
open (OUT, ">>$logfile");
print OUT "There was an error encountered while executing SQL- $dbh->errstr \n";
close(OUT);
}
You can also use $dbh->err; which returns the native Oracle error code to trap the error and exit accordingly.
The above, basic exception handling can be performed for every execute() method call in your script. Remember, DBI will have AutoCommit set to 1 (enabled) by default, unless explicitly disabled. So your transactions would be auto committed per insert, in order to handle the ATOMICITY of the entire transaction, you can disable autocommit and use $dbh->commit and $dbh->rollback to handle when you want to commit, or may be use some custom commit point (for larger sets of data).
Or the below can be used while connecting to the DB
$dbh = DBI->connect( "dbi:Oracle:abcdef", "username", "password" , {
PrintError => 0, ### Don't report errors via warn( )
RaiseError => 1 ### Do report errors via die( )
} );
this would automatically report all errors via die. The RaiseError is usually turned off by default.
Also if I understand you correctly then, by cron you mean you would be calling it from a shell cron job. In that case, call to your perl script from the cron itself can be redirected to log files something like below
perl your_perl.pl >> out.log 2>> err.log
out.log will contain regular logs and err.log will contain errors (specifically thrown by DBI prepare() or execute() methods too). In this case, you also need to make sure you use proper verbiage in print or die so that the logs look meaningful.
First, bear in mind that if you put an email address at the top of your crontab file any output from the cron job will be emailed to you:
MAILTO=me#mydomain.com
Second, if you set DBI's RaiseError to 1 when you connect you do not need to check every call, DBI will raise an error whenever one happens.
Third, DBI has an error handler callback. You register a handler and it is called whenever an error occurs with the handle in error and error text etc. If you return false from the error handler, DBI works as it would without the handler and goes on to die or warn. As a result, it is easier to set RaiseError and create an error handler than as Annjawn suggested.
Lastly, if you don't want to do this yourself, you can use something like DBIx::Log4perl and simply ask for it to log errors and nothing else. Any errors will be written to your Log4perl file and they include the SQL being executed, parameters etc.
How do I call informix stored procedures from Perl? I use DBD::ODBC to connect to informix database, but I don't know how to call procedures. my code like this:
my $dbh = DBI->connect("dbi:".DBDRIVE.":".DBNAME,DBUSER,DBPASS,
{RaiseError=>0,PrintError=>0,AutoCommit=>1}) ||
die $DBI::errstr;
$dbh->do("execute procedure sp_test('2010-05-01 00:00:00')") ||
warn "failed\n";
$dbh->disconnect();
When I run it, it didn't get error. But I get nothing when I check the database. The store procedure works fine if I run it in database directly.
Anyone can help me out?
As strange as it sounds, you need to fetch() from your statement handle in order to actually execute your stored procedure. Try changing your do() call to this instead:
my $sth = $dbh->prepare("execute procedure sp_test('2010-05-01 00:00:00')")
or die $dbh->errstr
$sth->execute() or die $dbh->errstr
$sth->fetch(); # SPL actually executed here
(You may also want to consider setting RaiseError => 1 in your connect() options to avoid having to do all the ... or die ... stuff after every call.)
Pass 1
I suppose DBDRIVE, DBNAME, DBUSER and DBPASS have been defined via the constant module:
use constant DBDRIVE => "informix"; # ...mitsake...
use constant DBNAME => "stores"; # Or whatever
use constant DBUSER => "me";
use constant DBPASS => "mine";
You should use 'or' rather than '||' after the call to DBI->connect().
From 'perldoc DBI':
$dbh = DBI−>connect($data_source, $username, $password, \%attr)
or die $DBI::errstr;
You can can get better help while resolving problems by using 'RaiseError=>1' and/or 'PrintError=>1'; that is what they are there for.
In general terms, the syntax of the EXECUTE PROCEDURE is correct, and should work OK as long as the procedure doesn't return anything...
Pass 2
Oh, you stipulate DBD::ODBC rather than DBD::Informix. Therefore, you are are at the mercy of a lot of code that I don't know so well as I know DBD::Informix.
Can we assume that you can connect to the database successfully using DBD::ODBC? And modify it and so on?
You will probably need to turn on the DBI tracing. You may also need to turn on lower level. Is the ODBC driver you are using provided by Informix, or is it the IBM DB2 CLI (C Common Client) driver, or one provided by someone else? Which version of Informix (IDS) are you using? Which platform are you running on? Which versions of Perl, DBI, DBD::ODBC and the various drivers are you using?
ODBC drivers can go munging SQL sent to it. I'm not clear what the various drivers I mentioned would do with the statement.
Pass 3
Did you consider contacting the dbi-users#perl.org mailing list? That's where the maintainers of DBI and DBD::ODBC hang out.
I'm in a web scripting class, and honestly and unfortunately, it has come second to my networking and design and analysis classes. Because of this I find I encounter problems that may be mundane but can't find the solution to it easily.
I am writing a CGI form that is supposed to work with a MySQL DB. I can insert and delete into the DB just fine. My problem comes when querying the DB.
My code compiles fine and I don't get errors when trying to "display" the info in the DB through the browser but the data and text doesn't in fact display. The code in question is here:
print br, 'test';
my $dbh = DBI->connect("DBI:mysql:austinc4", "*******", "*******", {RaiseError => 1} );
my $usersstatement = "select * from users";
my $projstatment = "select * from projects";
# Get the handle
my $userinfo = $dbh->query($usersstatement);
my $projinfo = $dbh->query($projstatement);
# Fetch rows
while (#userrow = $userinfo->fetchrow()) {
print $userrow[0], br;
}
print 'end';
This code is in an if statement that is surrounded by the print header, start_html, form, /form, end_html. I was just trying to debug and find out what was happening and printed the statements test and end. It prints out test but doesn't print out end. It also doesn't print out the data in my DB, which happens to come before I print out end.
What I believe I am doing is:
Connecting to my DB
Forming a string the contains the command/request to the DB
Getting a handle for my query I perform on the DB
Fetching a row from my handle
Printing the first field in the row I fetched from my table
But I don't see why my data wouldn't print out as well as the end text. I looked in DB and it does in fact contain data in the DB and the table that I am trying to get data from.
This one has got me stumped, so I appreciate any help. Thanks again. =)
Solution:
I was using a that wasn't supported by the modules I was including. This leads me to another question. How can I detect errors like this? My program does in fact compile correctly and the webpage doesn't "break". Aside from me double checking that all the methods I do use are valid, do I just see something like text not being displayed and assume that an error like this occurred?
Upon reading the comments, the reason your program is broken is because query() does not execute an SQL query. Therefore you are probably calling an undefined subroutine unless this is a wrapper you have defined elsewhere.
Here is my original posting of helpful hints, which still apply:
I hope you have use CGI, use DBI, etc... and use CGI::Carp and use strict;
Look in /var/log/apache2/access.log or error.log for the bugs
Realize that the first thing a CGI script prints MUST be a valid header or the web server and browser become unhappy and often nothing else displays.
Because of #3 print the header first BEFORE you do anything, especially before you connect to the database where the script may die or print something else because otherwise the errors or other messages will be emitted before the header.
If you still don't see an error go back to #2.
CGIs that use CGI.pm can be run from a command line in a terminal session without going through the webserver. This is also a good way to debug.