PHP - How To Manage Database Connections

Hi,

I would just like to know what limitations apply for opening X amount of connections to different websites with Curl? (specifically, I'm using Curl multi and have my own way of regulating how many connections occur at a given time).

I ask this because it seems I can open 100 connections and get the info from the websites quite quickly. If I were to open say 1000 would that crash my router or what would happen?

Thanks in advance!

Hey,

I would there be a way i could create a form in which upon entering a domain name/URL it will tell you how many connections there are to the site and how many (if any) MySQL queries are running?

If I add this line to a wordpress footer it displays the number of sql queries.

Code: [Select]
<?php echo get_num_queries(); ?> queries in <?php timer_stop(1); ?> seconds.

Any help is greatly appreciated.

Thanks.

Hi, I am quite new to using php classes so it maybe something simple here, however I am trying to establish to connection to two different databases using one PHP class; The problem is that this will work for one but when I create a new connection they will both fail.   

<?php
putenv("TZ=Europe/London");
 
// start database connection
$funky_db = new Database('xxxx', 'xxxx', 'xxxx', 'xxxx');
 
// start database connection
$funky_cc = new Database('xxxx', 'xxxx', 'xxxx', 'xxxx');
 
class Database {
 
    private $host;
    private $user;
    private $pass;
    private $name;
    private $link;
    private $error;
    private $errno;
    private $query;
 
    function __construct($host, $user, $pass, $name = "", $conn = 1) {
        $this -> host = $host;
        $this -> user = $user;
        $this -> pass = $pass;
        if (!empty($name)) $this -> name = $name;      
        if ($conn == 1) $this -> connect();
    }
 
    function __destruct() {
        @mysql_close($this->link);
    }
 
    public function connect() {
        if ($this -> link = mysql_connect($this -> host, $this -> user, $this -> pass, TRUE)) {
            if (!empty($this -> name)) {
                if (!mysql_select_db($this -> name)) $this -> exception("Could not connect to the database!");
            }
        } else {
            $this -> exception("Could not create database connection!");
        }
    }
 
    public function close() {
        @mysql_close($this->link);
    }
 
    public function query($sql) {
        if ($this->query = @mysql_query($sql)) {
            return $this->query;
        } else {
            $this->exception("Could not query database!".$this->name);
            return false;
        }
    }
 
    public function num_rows($qid) {
        if (empty($qid)) {         
            $this->exception("Could not get number of rows because no query id was supplied!");
            return false;
        } else {
            return mysql_num_rows($qid);
        }
    }
 
    public function fetch_array($qid) {
        if (empty($qid)) {
            $this->exception("Could not fetch array because no query id was supplied!");
            return false;
        } else {
            $data = mysql_fetch_array($qid);
        }
        return $data;
    }
 
    public function fetch_array_assoc($qid) {
        if (empty($qid)) {
            $this->exception("Could not fetch array assoc because no query id was supplied!");
            return false;
        } else {
            $data = mysql_fetch_array($qid, MYSQL_ASSOC);
        }
        return $data;
    }
 
public function fetch_object($qid) {
        if (empty($qid)) {
            $this->exception("Could not fetch object assoc because no query id was supplied!");
            return false;
        } else {
            $data = mysql_fetch_object($qid);
        }
        return $data;
    }
 
    public function fetch_all_array($sql, $assoc = true) {
        $data = array();
        if ($qid = $this->query($sql)) {
            if ($assoc) {
                while ($row = $this->fetch_array_assoc($qid)) {
                    $data[] = $row;
                }
            } else {
                while ($row = $this->fetch_array($qid)) {
                    $data[] = $row;
                }
            }
        } else {
            return false;
        }
        return $data;
    }
 
    public function last_id() {
        if ($id = mysql_insert_id()) {
            return $id;
        } else {
            return false;
        }
    }
 
    private function exception($message) {
        if ($this->link) {
            $this->error = mysql_error($this->link);
            $this->errno = mysql_errno($this->link);
        } else {
            $this->error = mysql_error();
            $this->errno = mysql_errno();
        }
        if (PHP_SAPI !== 'cli') {
        ?>
 
            <div class="alert-bad">
                <div>
                    Database Error
                </div>
                <div>
                    Message: <?php echo $message; ?>
                </div>
                <?php if (strlen($this->error) > 0): ?>
                    <div>
                        <?php echo $this->error; ?>
                    </div>
                <?php endif; ?>
                <div>
                    Script: <?php echo @$_SERVER['REQUEST_URI']; ?>
                </div>
                <?php if (strlen(@$_SERVER['HTTP_REFERER']) > 0): ?>
                    <div>
                        <?php echo @$_SERVER['HTTP_REFERER']; ?>
                    </div>
                <?php endif; ?>
            </div>
        <?php
        } else {
                    echo "MYSQL ERROR: " . ((isset($this->error) && !empty($this->error)) ? $this->error:'') . "\n";
        };
    }
 
}
?>

I was curious..  I read that after using a PDO connection you should set the object to null to close it out.  In this instance:

Code: [Select]
function IsOwner($regionid, $user) {
  global $Username, $SQL_Server, $SQL_User, $SQL_Pass;
  $pdo = new PDO("mysql:host=$SQL_Server;dbname=$SQL_Database", $SQL_User, $SQL_Pass);
  $sql = $pdo->prepare("SELECT count(region_id) FROM region_players WHERE region_id = ? AND user_id = ? AND owner = 1"); $sql->execute(array($regionid, $user));
  if ($sql->rowCount() == 0) { return false; } else { return true; }
  $pdo = null;
}

Since the return is called prior to the nulling, does it leave a connection hanging or does PHP do some sort of auto-closeout when a function ends?  Should I instead be doing:

Code: [Select]
function IsOwner($regionid, $user) {
  global $Username, $SQL_Server, $SQL_User, $SQL_Pass;
  $ownerstatus = false;
  $pdo = new PDO("mysql:host=$SQL_Server;dbname=$SQL_Database", $SQL_User, $SQL_Pass);
  $sql = $pdo->prepare("SELECT count(region_id) FROM region_players WHERE region_id = ? AND user_id = ? AND owner = 1"); $sql->execute(array($regionid, $user));
  if ($sql->rowCount() > 0) $ownerstatus = true;
  $pdo = null;  return $ownerstatus;
}

?

Hi,

Just a quick query.

I call my db connection and configuration files on every script.
I also have just made a functions script where i'm storing some functions
except when i call the function, my script fails because of a missing database connection.

But on the page that fails, i call the configuration files including the db connection at the start of the script.
 
But when i get to where i include the function they are all on the same script so should it fail??

The page did work fine when the function was inbedded in the script. But as i'm using the function on a few pages, i thought it would be better practise and more efficent to just include the function on each page i need, rather than just copy and paste all the php in the required pages.

Or do i have to declare the db connection inside the function page as well???

Thanks

Hi everybody,

I am facing "Too many connections" problem on my site.
in fact the server is moved from one location to,another and after the movement this problem arise...

Pls help.

Thanks

Hi

Have an issue with a script that connects to multiple Access databases to extract data.

There is one master database and then numerous small databases (I take no responsibility for the design!). The master is opened and then the sub databases are looped around, opened process and closed in turn.

However after about 20 connections I get the error [ODBC Microsoft Access Driver] Too many client tasks for any new connections. It is related to the number of connections rather than the number of operations on databases (ie, if I comment out one of the pieces of SQL run on each database it makes no difference).

I am closing the connection and unsetting the variable that stores the connection. As such there shouldn't be an excess of connections open at any one time.

Any suggestions?

All the best

Keith

Hello,

I'm trying to update my database with current statistics from my gameservers, but running the loop of socket connections to all of the servers on page load takes too long. For every server in the array it takes roughly 4 seconds to complete each one.. with a massive list of say 42 it takes awhile. However, I'm running from shared hosting and was wondering if that was the reason each server takes so long to query. I was thinking about running a cron job every 1 minute to update the information so it's still relativity new and current. Will the 1 minute cron job affect anything from the shared hosting? I'm using 1and1 web-hosting on a 1&1 Business Package.

Thanks

I've looked every where, probably googled every variation of my question I could come up with and I've tried all of the suggestions...  I'm trying to connect to two different DBs in two different locations ($local and $remote) and only the second one works.  Here is a sample of my code ("..." = hidden):

//-------------Local DB Connection:
    $local = mysql_connect("localhost","root","...");
    if (!$local)
    {
        die('Could not connect: ' . mysql_error());
    }
    $sel1 = mysql_select_db("new", $local);
//-------------Remote DB Connection:
    $remote = mysql_connect("...","...","...",true);
    if (!$remote)
    {
        die('Could not connect: ' . mysql_error());
    }
    $table = "...";

//---------function selecting from local:
    function fncGrabNemsis($ele,$val){
        mysql_select_db("new", $local);
        $result = mysql_query("SELECT * FROM new.tblvalues
        WHERE fldelement='$ele' AND fldcode='$val'",$local);
        $tmprow = mysql_fetch_array($result);
        return (isset($tmprow['fldvariable'])?$tmprow['fldvariable']:$val);
    }

//----------Select run from Remote:
        mysql_select_db("ImdxTest", $remote);
        $result = mysql_query("SELECT * FROM ImdxTest.$table WHERE ClientID = ... AND IncidentNum = '$fldINCID'", $remote) or die(mysql_error());
        $row = mysql_fetch_array($result);

I've tried moving the mysql_select_db() function calls everywhere you can think of and just about everything else...  What happens is, I get php errors saying that $local is not defined or that the mysql function that are trying to use the $local connection are expecting parameters to be resources!?  I know for a fact that both connections work because individually they both work.  Only the second connection ($remote) works...  Thanks a lot for any suggestions!

OK, so I dont think this is a code issue as such, but I am completely stumped as to where the issue could be.

I have a page with some standard include() functions at the top. When I access the page from home, everything operates as it should, when I access it from work (on multiple machines), I get the standard "unable to open stream" and "unable to access" warnings for the include statements. I have tried hard refreshing and deleting cache (not that it should make a shred of difference) etc, but the error is still there after a week or so.

Does anyone know what could be causing this issue?

Hello guys, I hope you can help.

I can't get my page to switch between two database connections properly
It seems to ignore the second connection.

I'm trying to go through each group in database one and find out how many members they have registered in database two by checking the field "tsName".

This is a valid query for database one.
$fetchUsers = mysql_query("SELECT * FROM $db_corps_table ORDER BY cName;", $con1);
This is a valid query for database two.
$fetchUsers = mysql_query("SELECT * FROM 'users' WHERE tsName LIKE $cTicker%;", $con2);
However despite me specifying which database link to use it tries to use every query on database one ($con1). So I can never query database two ($con2) because it just breaks with the result below. :S

$fetchUsers = mysql_query("SELECT * FROM $db_corps_table ORDER BY cName;", $con1); gives
Quote

AREA 43 [A-43] (11):
result
result
result
(there are 3 groups in database one)

But:
$fetchUsers = mysql_query("SELECT * FROM 'users' WHERE tsName LIKE $cTicker%;", $con2);  gives
Quote

AREA 43 [A-43] (11):

Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in /home/sever/public_html/mav/tools/ts_corp_registrations.php on line 51


<?php
// ===== Connect to database one (group) =====
$con1 = mysql_connect($db_host,$db_corps_user,$db_corps_pass);
if (!$con1) {
die("Could not connect:" . mysql_error());
}
$db_select1 = mysql_select_db($db_corps_db, $con1);
if (!$db_select1) {
die ("Could not select database:" . mysql_error());
}
// ===== Connect to database two (members) =====
$con2 = mysql_connect($db_host,$db_ts_user,$db_ts_pass, true);
if (!$con2) {
die("Could not connect:" . mysql_error());
}
$db_select2 = mysql_select_db($db_ts_db, $con2);
if (!$db_select2) {
die ("Could not select database:" . mysql_error());
}

$fetchCorps = mysql_query("SELECT * FROM $db_corps_table ORDER BY cName;", $con1);
while ($row = mysql_fetch_array($fetchCorps)) {
// For each of the results, gather details from database one, then see how many members we can find in database two 
$cName = $row["cName"];
$cTicker = mysql_real_escape_string($row["cTicker"],$con1);
$cMembers = $row["cMembers"];

echo $cName." [".$cTicker."] (".$cMembers."):<br />";
// ========================== HERE BE PROBLEMS ==========================
//$fetchUsers = mysql_query("SELECT * FROM $db_corps_table ORDER BY cName;", $con1);
$fetchUsers = mysql_query("SELECT * FROM 'users' WHERE tsName LIKE $cTicker%;", $con2);
// ===================================================================
while ($rowTS = mysql_fetch_array($fetchUsers)) {
echo "result<br />";
}
}
// all done, close DB connections
mysql_close($con2);
mysql_close($con1);
?>

after inserting data i get 0 sometimes
i created a mysql_connect for it


Code: [Select]
<?php
$maincon = mysql_connect('local', "root", "root");
mysql_select_db("root");


then

//insert and

$success = mysql_query($query);
echo $ref_id = mysql_insert_id($maincon);
?>
$ref_id is returned as 0, although the connection is there
var_dumping the query returns the values

Does anyone have an example of establishing two MySQL connections (one local & one external) to pass data from local DB to external using PHP?

Objective: I need to query the table of local data (for email addresses) then the same for external db table and if email not present, insert into that db.

I will use CRON to run the script (will figure that part out later but suggestions welcome if you have that info as well....)

How do I code a persistent connection with mysqli and PHP?
I know back in mysql it was mysqli_pconnect, what is it for mysqli?

Please do not refer to this page (http://www.php.net/manual/en/mysqli.persistconns.php) as it gives no example and makes little sense.

Many thanks in advance.

Over the past few days I have been running into some issues with my server crashing due to apache max connections issues. I am running my site off of a hosted Cloud VPS with 200GB of storage, 8192MB Memory, 8TB of transfer, Apache, MySQL, PHP5, and CentOS.   I am afraid the issue doesn't necessarily lay in the configuration of Apache, but the way I have scripted the php on my site, the reason I am reaching out here. My site isn't your average website, it is more of a web-based customer management program. There are currently only 2 pages you can actually access via the url bar (signin.php and index.php). All other content is loaded via AJAX and JQuery processes (.load and $.getScript).   All AJAX requests are pointed toward a single file called functions.php where a _POST parameter contains the function name and any additional _POST data required by the function.   FOR EXAMPLE:   AJAX Call:

$.post('functions/functions.php',{func:'myFunctionName',ops:'whatever',a:'whatever',b:'whatever'},function(data){
         DO WHATEVER I WANT WITH THE RETURN DATA HERE
},"json");

PHP (functions.php)

require 'dbcon.php';
include 'main_class.php';
include 'f_customerdetail.php';
include 'f_listoptions.php';
include 'f_route.php';
include 'f_useractions.php';

if (isset($_POST['func'])){ 
   $userfunc = $_POST['func']; 
   $funcops = $_POST['ops'];

   if ($funcops != ''){ 
      $userfunc($funcops); 
   }else{ 
      $userfunc(); 
   } 
}