Performance issues

Many thanks apmuthu all is good now
may i ask how i can register my name as frontaccounting developer contributor

It is imperative for the stock_id field to be indexed in the debtor_trans_details table for all FA databases used with the equivalent of:

ALTER TABLE `0_debtor_trans_details` ADD INDEX `stock_trans` (`stock_id`);

The function get_customer_trans_details() in the file sales/icludes/db/cust_trans_details_db.inc is used in reporting/rep107.php (and in 110, 113 reports as well) to acquire the transaction list filtered as appropriate. The non filtered SQL in it is:

SELECT trans.*,
       trans.unit_price + trans.unit_tax AS FullUnitPrice,
       trans.description AS StockDescription,
       stock.units,
       stock.mb_flag
FROM 0_debtor_trans_details trans
        INNER JOIN 0_stock_master stock USING (stock_id)
ORDER BY id;

As the stock_master.stock_id and debtor_trans_details.id fields are primary keys, they stand already indexed. Hence the foreign key debtor_trans_details.stock_id is the one that is left to be indexed as it is the INNER JOIN field.

The said function can be modified to be:

function get_customer_trans_details($debtor_trans_type, $debtor_trans_no)
{
    if (!is_array($debtor_trans_no))
        $debtor_trans_no = array( 0=>$debtor_trans_no );
    $sql = "SELECT trans.*,
        trans.unit_price + trans.unit_tax AS FullUnitPrice,
        trans.description As StockDescription,
        stock.units, stock.mb_flag
        FROM ".TB_PREF."debtor_trans_details trans
             INNER JOIN ".TB_PREF."stock_master stock USING (stock_id)
         WHERE (";

    $tr=array();
    foreach ($debtor_trans_no as $trans_no)
        $tr[] = 'debtor_trans_no='.db_escape($trans_no);
    $sql .= implode(' OR ', $tr);

    $sql.=    ") AND debtor_trans_type=".db_escape($debtor_trans_type)."
        ORDER BY id";
    return db_query($sql, "The debtor transaction detail could not be queried");
}

@joe: want to include it in the core? Committed in my FAMods.

I can confirm that even after this, when a range of invoices is attempted to be printed, the webserver hangs. Single invoice printing works. Multi Invoice (range) printing fails at second invoice call of function get_sales_parent_lines() in file sales/includes/sales_db.inc.
In the first invoice call in the Training Co (Demo Co) it succeeds:

SELECT parent.*
FROM 1_debtor_trans_details parent
    LEFT JOIN 0_debtor_trans_details trans 
        ON trans.src_id=parent.id
WHERE trans.debtor_trans_type='10' 
  AND trans.debtor_trans_no='17' 
GROUP BY parent.debtor_trans_no 
ORDER BY parent.debtor_trans_no;

SQL SELECT debug Trail attached.

Web Server hangs when the statement $rep->NewPage() tries to get executed for the second page in rep107.php - tested in XAMPP v1.7.3 on WinXP SP3 / FireFox v37.0.

On further investigation, it appears that the logo width, if too high only results in truncation of image when displayed in the report header.

Some sort of cache may be playing havoc.

The solution is to
1. upload some other Company logo (Setup -> Company Setup) and update the company and then
2. revert back to the original logo and update the company and then
3. print range of invoices

Attached is a set of logos of varying widths and the way they get displayed in the Invoice header.

It is probably the scaling (rounding off) of the height with respect to the actual width (if smaller) or that of the width if the height is smaller, that may be the cause of the error. Any way to avoid scaling altogether as distortion occurs sometimes?

3gp volume of data is too heavy for your server. You better increase your RAM speed and cache size to get the your FA work faster like before.  It's not in code issue,  I feel you have to increase your system speed.