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Low performance when reading large LOB

michal.taborskyAug 22 2013 — edited Aug 23 2013

Hello everyone,

we need to read a file of about 70M from from database LOB and send it to clients. Dead simple:

<?php

$id = 'filename';

$c = oci_connect('scott', 'tiger', 'MYCONN');

$sql = "SELECT CONTENT FROM MYTABLE WHERE ID=:1";

$s = oci_parse($c, $sql);

oci_bind_by_name($s, ':1', $id);

$r = oci_execute($s);

$arr = oci_fetch_array($s, OCI_ASSOC);

if (is_object($arr['CONTENT'])) {

  while (!$arr['CONTENT']->eof()) {

    echo $arr['CONTENT']->read(1000000);

  }

}

All works fine, only performance sucks. This script, for the 70 meg file, takes 40 seconds(!) and the transfer speed is below 2MB/s. The app server is connected to the database with gigabit ethernet, tested transfer speed (tested with scp) between app server and database is over 100MB/s, as is to be expected. The database and the app server are both underutilized beefy machines. I tried various chunk sizes for the read method, but the variations in speed are insignificant. I tried SQL*Net tracing on the client, there are no errors reported. There is no special SQL*Net configuration either on the client, nor server.

Anyone has any experience with tuning this? I am sure we can do much better.

Thanks for any hints,

Michal

Comments

1003714

First of all 64-bit builds of Java do no have the auto-update feature. So you should only have to worry about Java using 32-bit (x86). You can turn off the AU a number of ways. Create a file called "Java Policy - Disable Auto Updates.reg" and paste the following text into it.

Windows Registry Editor Version 5.00




[HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Update\Policy]


"EnableJavaUpdate"=dword:00000000

Then if you have a batch file you use to install Java on the workstation then just add the following lines to the batch file:

XCOPY "\\10.10.5.100\Java_Updates\*.reg" "C:\Java_Updates\" /E /Y /V /I /Q /R


CD "C:\Java_Updates\"


RegEdit /s "Java Policy - Disable Auto Updates.reg"

You can also look up what's called a deployment.properties file (or d.p). It usually goes into "C:\Windows\Sun\Java\Deployment" and you can list different properties that you'd see in the control panel. Then you can set the default values and/or lock that property so users cannot change them. Keep in mind that this d.p file is mostly broken in some of the latest builds of v7.

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Locked on Sep 20 2013
Added on Aug 22 2013
#performance, #php
2 comments
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