mysql_real_escape_string memory leak?

[vivek]

Could someone please help me figure out why the memory usage
fluctuates when I use mysql_real_escape_string? I'm finding (what I
think are) memory leaks with a few mysql functions in php and I'm
trying to figure them all out. This one is pretty vexing. Thanks in
advance.

Here is example code:
class memTest {
function __construct() {
$con = mysql_connect("***************","*******","****");
if (!$con) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db("*******", $con);
mysql_query("SET NAMES 'utf8'");
for ($i = 1; $i<=10; $i++) {
$temp = 'mysql';
echo "mem: ", memory_get_usage(), "\n";
echo mysql_real_escape_string($temp), "\n";
echo "mem: ", memory_get_usage(), "\n\n";
}
mysql_close($con);
}
}
$a = new memTest();

Here is what is output:
mem: 43216
mysql
mem: 43208

mem: 43208
mysql
mem: 43216

mem: 43216
mysql
mem: 43224

mem: 43224
mysql
mem: 43232

mem: 43232
mysql
mem: 43240

mem: 43240
mysql
mem: 43248

mem: 43248
mysql
mem: 43256

mem: 43256
mysql
mem: 43264

mem: 43264
mysql
mem: 43272

mem: 43272
mysql
mem: 43280

[=?ISO-8859-15?Q?Iv=E1n_S=E1nchez_Ortega?=]

vi***@thoughtconvergence.com wrote:

Could someone please help me figure out why the memory usage
fluctuates when I use mysql_real_escape_string? I'm finding (what I
think are) memory leaks with a few mysql functions in php and I'm
trying to figure them all out. This one is pretty vexing. Thanks in
advance.

Sorry, not able to reproduce here:

mem: 99552
mysql
mem: 99552

mem: 99552
mysql
mem: 99552

mem: 99552
mysql
mem: 99552

mem: 99552
mysql
mem: 99552

(Keep in mind that I use a amd64 processor, so the 64-bit addresses waste a
lot of memory).
Question: does the memory usage go up and up, or does the garbage collector
come after some time (hint: go wild with the loop count)?? You may just be
creating temporal variables to hold the result of mysql_real_escape_string,
that aren't collected thereafter.
--
----------------------------------
Iván Sánchez Ortega -ivansanchez-algarroba-escomposlinux-punto-org-

http://acm.asoc.fi.upm.es/~mr/
Proudly running Debian Linux with 2.6.20-1-amd64 kernel, KDE 3.5.7, and PHP
5.2.3-1 generating this signature.
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1.95

[Jerry Stuckle]

vi***@thoughtconvergence.com wrote:

Could someone please help me figure out why the memory usage
fluctuates when I use mysql_real_escape_string? I'm finding (what I
think are) memory leaks with a few mysql functions in php and I'm
trying to figure them all out. This one is pretty vexing. Thanks in
advance.

Here is example code:
class memTest {
function __construct() {
$con = mysql_connect("***************","*******","****");
if (!$con) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db("*******", $con);
mysql_query("SET NAMES 'utf8'");
for ($i = 1; $i<=10; $i++) {
$temp = 'mysql';
echo "mem: ", memory_get_usage(), "\n";
echo mysql_real_escape_string($temp), "\n";
echo "mem: ", memory_get_usage(), "\n\n";
}
mysql_close($con);
}
}
$a = new memTest();

Here is what is output:
mem: 43216
mysql
mem: 43208

mem: 43208
mysql
mem: 43216

mem: 43216
mysql
mem: 43224

mem: 43224
mysql
mem: 43232

mem: 43232
mysql
mem: 43240

mem: 43240
mysql
mem: 43248

mem: 43248
mysql
mem: 43256

mem: 43256
mysql
mem: 43264

mem: 43264
mysql
mem: 43272

mem: 43272
mysql
mem: 43280

And you're worried about *164 bytes* of memory?

Do you actually have a problem? Or are you doing "premature optimization"?

--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
js*******@attglobal.net
==================

[vivek]

On Jul 3, 6:42 pm, Jerry Stuckle <[e-mail]:

[e-mail] wrote:

Could someone please help me figure out why the memory usage
fluctuates when I use mysql_real_escape_string? I'm finding (what I
think are) memory leaks with a few mysql functions in php and I'm
trying to figure them all out. This one is pretty vexing. Thanks in
advance.

Here is example code:
class memTest {
function __construct() {
$con = mysql_connect("***************","*******","****");
if (!$con) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db("*******", $con);
mysql_query("SET NAMES 'utf8'");
for ($i = 1; $i<=10; $i++) {
$temp = 'mysql';
echo "mem: ", memory_get_usage(), "\n";
echo mysql_real_escape_string($temp), "\n";
echo "mem: ", memory_get_usage(), "\n\n";
}
mysql_close($con);
}
}
$a = new memTest();

Here is what is output:
mem: 43216
mysql
mem: 43208

mem: 43208
mysql
mem: 43216

mem: 43216
mysql
mem: 43224

mem: 43224
mysql
mem: 43232

mem: 43232
mysql
mem: 43240

mem: 43240
mysql
mem: 43248

mem: 43248
mysql
mem: 43256

mem: 43256
mysql
mem: 43264

mem: 43264
mysql
mem: 43272

mem: 43272
mysql
mem: 43280

And you're worried about *164 bytes* of memory?

Do you actually have a problem? Or are you doing "premature optimization"?

--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
[e-mail]
==================

I am doing premature optimization. Eventually I'm going to be looping
~3.5 million times and inserting data into a table, so any memory leak
will be a problem.

Interestingly, when I increase the loop count to 1000, the memory
seems to stop increasing and stabilizes at iteration 256 (2^8). Prior
to that, the memory usage increases by 8 bytes each iteration. I'd
like to know why it increases in the first place, and how to prevent
it from increasing. Is there a way to force garbage collection in php?

[Jerry Stuckle]

vi***@thoughtconvergence.com wrote:

On Jul 3, 6:42 pm, Jerry Stuckle <[e-mail]:

>[e-mail] wrote:

>>Could someone please help me figure out why the memory usage
fluctuates when I use mysql_real_escape_string? I'm finding (what I
think are) memory leaks with a few mysql functions in php and I'm
trying to figure them all out. This one is pretty vexing. Thanks in
advance.
Here is example code:
class memTest {
function __construct() {
$con = mysql_connect("***************","*******","****");
if (!$con) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db("*******", $con);
mysql_query("SET NAMES 'utf8'");
for ($i = 1; $i<=10; $i++) {
$temp = 'mysql';
echo "mem: ", memory_get_usage(), "\n";
echo mysql_real_escape_string($temp), "\n";
echo "mem: ", memory_get_usage(), "\n\n";
}
mysql_close($con);
}
}
$a = new memTest();
Here is what is output:
mem: 43216
mysql
mem: 43208
mem: 43208
mysql
mem: 43216
mem: 43216
mysql
mem: 43224
mem: 43224
mysql
mem: 43232
mem: 43232
mysql
mem: 43240
mem: 43240
mysql
mem: 43248
mem: 43248
mysql
mem: 43256
mem: 43256
mysql
mem: 43264
mem: 43264
mysql
mem: 43272
mem: 43272
mysql
mem: 43280

And you're worried about *164 bytes* of memory?

Do you actually have a problem? Or are you doing "premature optimization"?

--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
[e-mail]
==================

I am doing premature optimization. Eventually I'm going to be looping
~3.5 million times and inserting data into a table, so any memory leak
will be a problem.

Interestingly, when I increase the loop count to 1000, the memory
seems to stop increasing and stabilizes at iteration 256 (2^8). Prior
to that, the memory usage increases by 8 bytes each iteration. I'd
like to know why it increases in the first place, and how to prevent
it from increasing. Is there a way to force garbage collection in php?

Nope, no way to force garbage collection. It's not a separate thread
like in Java; the interpreter will clean things up when it gets around
to it.

But again, I wouldn't worry about it until you have a problem. With
3.5M iterations, you'll have other problems than memory leaks - for
instance, it's probably going to take a lot of time to do that many
inserts into a database.
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
js*******@attglobal.net
==================

[=?ISO-8859-15?Q?Iv=E1n_S=E1nchez_Ortega?=]

Jerry Stuckle wrote:

>Is there a way to force garbage collection in php?

Nope, no way to force garbage collection. It's not a separate thread
like in Java; the interpreter will clean things up when it gets around
to it.

But again, I wouldn't worry about it until you have a problem. With
3.5M iterations, you'll have other problems than memory leaks - for
instance, it's probably going to take a lot of time to do that many
inserts into a database.

And it would take even more time if you forced the garbage collector to run
more frequently than needed...

Instead of that, try experimenting with prepared statements, COPY
statements and different DB interfaces; those decisions can lead to very
different times when inserting that volume of information in the DB.

--
----------------------------------
Iván Sánchez Ortega -ivansanchez-algarroba-escomposlinux-punto-org-

http://acm.asoc.fi.upm.es/~mr/
Proudly running Debian Linux with 2.6.20-1-amd64 kernel, KDE 3.5.7, and PHP
5.2.3-1+b1 generating this signature.
Uptime: 21:37:58 up 20 days, 5:08, 5 users, load average: 3.24, 3.37,
1.52