PHP uses more memory than the file required
Take the given example code:
<?php
if (! function_exists('human_filesize')) {
function human_filesize($size, $precision = 2, $step = 1000)
{
$i = 0;
$units = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
while (($size / $step) > 0.9) {
$size = $size / $step;
$i++;
}
return round($size, $precision) . ' ' . $units[$i];
}
}
if (! function_exists('dd')) {
function dd($vars)
{
foreach (func_get_args() as $var) {
var_dump($var);
}
die();
}
}
$start = microtime(true);
$usage = memory_get_usage(true);
require "brown_corpus.php"; // It's 1.6 MB
$dump = round(microtime(true) - $start, 3);
$dump = human_filesize(memory_get_usage(true) - $usage);
dd(...$dump); // 0.063ms to run | 38.01 MB memory used
brown_corpus.php is 1.6 MB, but when it's required the script tells me it's using 38.01 MB in memory. I've been doing some reading and I'm wondering if this is because PHP compiles required files into opcode, for faster execution? Can someone enlighten be on the pros and cons of this... i.e. if I go ahead and search for keys within an array in that requirement, is that now faster - because of the way PHP has compiled the file?
php memory memory-management
asked Nov 24 '18 at 17:33
LukaLuka
1289
add a comment |
Take the given example code:
<?php
if (! function_exists('human_filesize')) {
function human_filesize($size, $precision = 2, $step = 1000)
{
$i = 0;
$units = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
while (($size / $step) > 0.9) {
$size = $size / $step;
$i++;
}
return round($size, $precision) . ' ' . $units[$i];
}
}
if (! function_exists('dd')) {
function dd($vars)
{
foreach (func_get_args() as $var) {
var_dump($var);
}
die();
}
}
$start = microtime(true);
$usage = memory_get_usage(true);
require "brown_corpus.php"; // It's 1.6 MB
$dump = round(microtime(true) - $start, 3);
$dump = human_filesize(memory_get_usage(true) - $usage);
dd(...$dump); // 0.063ms to run | 38.01 MB memory used
brown_corpus.php is 1.6 MB, but when it's required the script tells me it's using 38.01 MB in memory. I've been doing some reading and I'm wondering if this is because PHP compiles required files into opcode, for faster execution? Can someone enlighten be on the pros and cons of this... i.e. if I go ahead and search for keys within an array in that requirement, is that now faster - because of the way PHP has compiled the file?
php memory memory-management
asked Nov 24 '18 at 17:33
LukaLuka
1289
add a comment |
Take the given example code:
<?php
if (! function_exists('human_filesize')) {
function human_filesize($size, $precision = 2, $step = 1000)
{
$i = 0;
$units = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
while (($size / $step) > 0.9) {
$size = $size / $step;
$i++;
}
return round($size, $precision) . ' ' . $units[$i];
}
}
if (! function_exists('dd')) {
function dd($vars)
{
foreach (func_get_args() as $var) {
var_dump($var);
}
die();
}
}
$start = microtime(true);
$usage = memory_get_usage(true);
require "brown_corpus.php"; // It's 1.6 MB
$dump = round(microtime(true) - $start, 3);
$dump = human_filesize(memory_get_usage(true) - $usage);
dd(...$dump); // 0.063ms to run | 38.01 MB memory used
brown_corpus.php is 1.6 MB, but when it's required the script tells me it's using 38.01 MB in memory. I've been doing some reading and I'm wondering if this is because PHP compiles required files into opcode, for faster execution? Can someone enlighten be on the pros and cons of this... i.e. if I go ahead and search for keys within an array in that requirement, is that now faster - because of the way PHP has compiled the file?
php memory memory-management
asked Nov 24 '18 at 17:33
LukaLuka
1289
Take the given example code:
<?php
if (! function_exists('human_filesize')) {
function human_filesize($size, $precision = 2, $step = 1000)
{
$i = 0;
$units = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
while (($size / $step) > 0.9) {
$size = $size / $step;
$i++;
}
return round($size, $precision) . ' ' . $units[$i];
}
}
if (! function_exists('dd')) {
function dd($vars)
{
foreach (func_get_args() as $var) {
var_dump($var);
}
die();
}
}
$start = microtime(true);
$usage = memory_get_usage(true);
require "brown_corpus.php"; // It's 1.6 MB
$dump = round(microtime(true) - $start, 3);
$dump = human_filesize(memory_get_usage(true) - $usage);
dd(...$dump); // 0.063ms to run | 38.01 MB memory used
brown_corpus.php is 1.6 MB, but when it's required the script tells me it's using 38.01 MB in memory. I've been doing some reading and I'm wondering if this is because PHP compiles required files into opcode, for faster execution? Can someone enlighten be on the pros and cons of this... i.e. if I go ahead and search for keys within an array in that requirement, is that now faster - because of the way PHP has compiled the file?
php memory memory-management
php memory memory-management
asked Nov 24 '18 at 17:33
LukaLuka
1289
asked Nov 24 '18 at 17:33
LukaLuka
1289
asked Nov 24 '18 at 17:33
LukaLuka
1289
asked Nov 24 '18 at 17:33
LukaLuka
1289
asked Nov 24 '18 at 17:33
LukaLuka
1289
1289
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
The size of the file has no bearing on the amount of memory it consumes. Without seeing brown_corpus.php, it's impossible to know how it is consuming memory, but keep in mind that code is (usually) a condensed way of describing the structures that it actually creates. Consider the following:
$arr = array();
for ($i = 0; $i < 100000; $i++) {
$arr[$i] = $i;
}
Save this into a php file and it occupies about 70 bytes. Run it and it will create an array structure containing 100,000 elements, each of which is an 8-byte integer. Boom, 800 kilobytes used.
In practice it's far worse than this because of how PHP is configured on your system, to say nothing of various sorts of overheads PHP imposes (the manner in which it stores arrays, for example, boggles the mind -- see https://nikic.github.io/2011/12/12/How-big-are-PHP-arrays-really-Hint-BIG.html).
answered Nov 28 '18 at 1:00
Phl3tchPhl3tch
13838
Those articles seem to really explain this well.brown_corpuscontains a returned array of lots of key / value pairs. So that would explain how more bytes are being consumed when required into memory. I wonder if a DB look up might be better, but the script will surely take longer to run, yet be less memory intensive. Giving bounty shortly...
– Luka
Nov 28 '18 at 13:51
Yes, and different types use widely ranging amounts of memory. You can do memory_get_usage() before and after any variable assignments to get a rough idea how much is being used for that type or structure, but the values will vary from system to system. If you're looking to compare different approaches timing-wise, I'd recommend using microtime() to measure the time taken by each. See the first example on php.net/manual/en/function.microtime.php.
– Phl3tch
Nov 28 '18 at 21:23
add a comment |
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1 Answer
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1 Answer
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oldest
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oldest
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active
oldest
votes
The size of the file has no bearing on the amount of memory it consumes. Without seeing brown_corpus.php, it's impossible to know how it is consuming memory, but keep in mind that code is (usually) a condensed way of describing the structures that it actually creates. Consider the following:
$arr = array();
for ($i = 0; $i < 100000; $i++) {
$arr[$i] = $i;
}
Save this into a php file and it occupies about 70 bytes. Run it and it will create an array structure containing 100,000 elements, each of which is an 8-byte integer. Boom, 800 kilobytes used.
In practice it's far worse than this because of how PHP is configured on your system, to say nothing of various sorts of overheads PHP imposes (the manner in which it stores arrays, for example, boggles the mind -- see https://nikic.github.io/2011/12/12/How-big-are-PHP-arrays-really-Hint-BIG.html).
answered Nov 28 '18 at 1:00
Phl3tchPhl3tch
13838
Those articles seem to really explain this well.brown_corpuscontains a returned array of lots of key / value pairs. So that would explain how more bytes are being consumed when required into memory. I wonder if a DB look up might be better, but the script will surely take longer to run, yet be less memory intensive. Giving bounty shortly...
– Luka
Nov 28 '18 at 13:51
Yes, and different types use widely ranging amounts of memory. You can do memory_get_usage() before and after any variable assignments to get a rough idea how much is being used for that type or structure, but the values will vary from system to system. If you're looking to compare different approaches timing-wise, I'd recommend using microtime() to measure the time taken by each. See the first example on php.net/manual/en/function.microtime.php.
– Phl3tch
Nov 28 '18 at 21:23
add a comment |
The size of the file has no bearing on the amount of memory it consumes. Without seeing brown_corpus.php, it's impossible to know how it is consuming memory, but keep in mind that code is (usually) a condensed way of describing the structures that it actually creates. Consider the following:
$arr = array();
for ($i = 0; $i < 100000; $i++) {
$arr[$i] = $i;
}
Save this into a php file and it occupies about 70 bytes. Run it and it will create an array structure containing 100,000 elements, each of which is an 8-byte integer. Boom, 800 kilobytes used.
In practice it's far worse than this because of how PHP is configured on your system, to say nothing of various sorts of overheads PHP imposes (the manner in which it stores arrays, for example, boggles the mind -- see https://nikic.github.io/2011/12/12/How-big-are-PHP-arrays-really-Hint-BIG.html).
answered Nov 28 '18 at 1:00
Phl3tchPhl3tch
13838
Those articles seem to really explain this well.brown_corpuscontains a returned array of lots of key / value pairs. So that would explain how more bytes are being consumed when required into memory. I wonder if a DB look up might be better, but the script will surely take longer to run, yet be less memory intensive. Giving bounty shortly...
– Luka
Nov 28 '18 at 13:51
Yes, and different types use widely ranging amounts of memory. You can do memory_get_usage() before and after any variable assignments to get a rough idea how much is being used for that type or structure, but the values will vary from system to system. If you're looking to compare different approaches timing-wise, I'd recommend using microtime() to measure the time taken by each. See the first example on php.net/manual/en/function.microtime.php.
– Phl3tch
Nov 28 '18 at 21:23
add a comment |
The size of the file has no bearing on the amount of memory it consumes. Without seeing brown_corpus.php, it's impossible to know how it is consuming memory, but keep in mind that code is (usually) a condensed way of describing the structures that it actually creates. Consider the following:
$arr = array();
for ($i = 0; $i < 100000; $i++) {
$arr[$i] = $i;
}
Save this into a php file and it occupies about 70 bytes. Run it and it will create an array structure containing 100,000 elements, each of which is an 8-byte integer. Boom, 800 kilobytes used.
In practice it's far worse than this because of how PHP is configured on your system, to say nothing of various sorts of overheads PHP imposes (the manner in which it stores arrays, for example, boggles the mind -- see https://nikic.github.io/2011/12/12/How-big-are-PHP-arrays-really-Hint-BIG.html).
answered Nov 28 '18 at 1:00
Phl3tchPhl3tch
13838
The size of the file has no bearing on the amount of memory it consumes. Without seeing brown_corpus.php, it's impossible to know how it is consuming memory, but keep in mind that code is (usually) a condensed way of describing the structures that it actually creates. Consider the following:
$arr = array();
for ($i = 0; $i < 100000; $i++) {
$arr[$i] = $i;
}
Save this into a php file and it occupies about 70 bytes. Run it and it will create an array structure containing 100,000 elements, each of which is an 8-byte integer. Boom, 800 kilobytes used.
In practice it's far worse than this because of how PHP is configured on your system, to say nothing of various sorts of overheads PHP imposes (the manner in which it stores arrays, for example, boggles the mind -- see https://nikic.github.io/2011/12/12/How-big-are-PHP-arrays-really-Hint-BIG.html).
answered Nov 28 '18 at 1:00
Phl3tchPhl3tch
13838
answered Nov 28 '18 at 1:00
Phl3tchPhl3tch
13838
answered Nov 28 '18 at 1:00
Phl3tchPhl3tch
13838
answered Nov 28 '18 at 1:00
Phl3tchPhl3tch
13838
13838
Those articles seem to really explain this well.brown_corpuscontains a returned array of lots of key / value pairs. So that would explain how more bytes are being consumed when required into memory. I wonder if a DB look up might be better, but the script will surely take longer to run, yet be less memory intensive. Giving bounty shortly...
– Luka
Nov 28 '18 at 13:51
Yes, and different types use widely ranging amounts of memory. You can do memory_get_usage() before and after any variable assignments to get a rough idea how much is being used for that type or structure, but the values will vary from system to system. If you're looking to compare different approaches timing-wise, I'd recommend using microtime() to measure the time taken by each. See the first example on php.net/manual/en/function.microtime.php.
– Phl3tch
Nov 28 '18 at 21:23
add a comment |
Those articles seem to really explain this well.brown_corpuscontains a returned array of lots of key / value pairs. So that would explain how more bytes are being consumed when required into memory. I wonder if a DB look up might be better, but the script will surely take longer to run, yet be less memory intensive. Giving bounty shortly...
– Luka
Nov 28 '18 at 13:51
Yes, and different types use widely ranging amounts of memory. You can do memory_get_usage() before and after any variable assignments to get a rough idea how much is being used for that type or structure, but the values will vary from system to system. If you're looking to compare different approaches timing-wise, I'd recommend using microtime() to measure the time taken by each. See the first example on php.net/manual/en/function.microtime.php.
– Phl3tch
Nov 28 '18 at 21:23
Those articles seem to really explain this well.
brown_corpus contains a returned array of lots of key / value pairs. So that would explain how more bytes are being consumed when required into memory. I wonder if a DB look up might be better, but the script will surely take longer to run, yet be less memory intensive. Giving bounty shortly...– Luka
Nov 28 '18 at 13:51
Those articles seem to really explain this well.
brown_corpus contains a returned array of lots of key / value pairs. So that would explain how more bytes are being consumed when required into memory. I wonder if a DB look up might be better, but the script will surely take longer to run, yet be less memory intensive. Giving bounty shortly...– Luka
Nov 28 '18 at 13:51
Yes, and different types use widely ranging amounts of memory. You can do memory_get_usage() before and after any variable assignments to get a rough idea how much is being used for that type or structure, but the values will vary from system to system. If you're looking to compare different approaches timing-wise, I'd recommend using microtime() to measure the time taken by each. See the first example on php.net/manual/en/function.microtime.php.
– Phl3tch
Nov 28 '18 at 21:23
Yes, and different types use widely ranging amounts of memory. You can do memory_get_usage() before and after any variable assignments to get a rough idea how much is being used for that type or structure, but the values will vary from system to system. If you're looking to compare different approaches timing-wise, I'd recommend using microtime() to measure the time taken by each. See the first example on php.net/manual/en/function.microtime.php.
– Phl3tch
Nov 28 '18 at 21:23
add a comment |
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