CENTOS PHP PDO ODBC MSSQL 2008 r2

Question

2 days ago, SQL Admin made upgrade of MSSQL from 2008 to 2008 R2. Before this upgrade,I worked with MSSQL by FreeTDS, but after upgrade I couldn't read any output parameter from stored procedures. So I installed official ODBC driver from Microsoft Site for Linux (I'm using CentoOS 64) Now: I can connect, make a simple query, but I can't catch any output parameter from stored procedure and also I can't catch query output:

select OutputString from tTableOutput where ID = 5 

where OuptutString contain large xml.

I try PDO, ODBC and all not working. If I use PDO:

$result = $db->query("select OutputString from tTableOutput with(nolock) where ID = 5");
foreach ($result as $row) {
    print_r($row);
}

I get:

PHP Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[01004]: String data, right truncated: 0 [Microsoft][ODBC Driver 11 for SQL Server]String data, right truncation (SQLFetchScroll[0] at /builddir/build/BUILD/php-5.3.3/ext/pdo_odbc/odbc_stmt.c:528 )

How can increase length limit ?

If I use ODBC:

$conn = odbc_connect($dataSource,$user,$password);
$sql = "select OutputString from tTableOutput where ID = 5";

$rs=odbc_exec($conn,$sql);
odbc_binmode ($rs, ODBC_BINMODE_PASSTHRU);
odbc_longreadlen ($rs, 0);

if (!$rs){
    exit("Error in SQL");
}
while (odbc_fetch_row($rs)){
    print_r(odbc_result($rs, "OutputString"));

}
odbc_close($conn);

I get:

PHP Fatal error:  Allowed memory size of 536870912 bytes exhausted (tried to allocate 4294967293 bytes)

Why this query need 4GB of memory ?

I would appreciate for any help

Answer 1

I would guess (A driver manager trace might show more) that the driver is describing the result column as a blob/clob/var(max) type and it will be returning a length of either 4Gb or maybe -1. If PHP is deciding to attempt to allocate that much it will fail as you see. I would say its a flaw in PHP. You could try converting the XML column into a TEXT type, that might convince PHP its a longdata type and not to try and save it in one chunk. In the Easysoft driver we added a flag to limit the reported size of long types to avoid this, but thats not much help with the MS driver.

Answer 2

You can try to cast the value as varchar(size of your choice).

ie Change the line:

select OutputString from tTableOutput where ID = 5 

to

select cast(OutputString as varchar(255)) from tTableOutput where ID = 5 

This will prevent the query to report a size of 4GB.