389704 - Large memory leak when changing textarea.value

Status: UNCONFIRMED

(Core :: DOM: Core & HTML, defect, P5)

Description

[Yann Hamon]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.3) Gecko/20061201 Firefox/2.0.0.3 (Ubuntu-feisty)
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.3) Gecko/20061201 Firefox/2.0.0.3 (Ubuntu-feisty)

Hello, 

I built a javascript "logging" in a textarea; like textarea += text, and this 3000 times. The more text there is, the more memory it uses, and the fastest the memory footprint grows. 
The exact line was:

document.getElementById("pl_dokukiwix_log").value += currentHours+":"+currentMinutes+":"+currentSeconds+" "+logstring+"\n";

This line (after being called 1000 times) caused firefox to use over 500MB of memory; deleting this line solved the memory problem.


Reproducible: Always

Steps to Reproduce:
1.
2.
3.

Comment 1

[Olli Pettay [:smaug]]

Minimal testcase would be great.

Comment 2

[Aiko]

Attachment: testcase

I tested the latest trunk nightly under WinXP with 300 iterations, 1000 took far too long. You could also take a look at the testcase for bug 190147.

With this test, I get the following numbers for firefox.exe's VM Size as reported by Task Manager:

New start with testcase loaded: 23332K.
Press the first button, VM Size climbs to 23672K.
Press the second button, VM Size climbs from 23672K to 58328K.
Leave the browser alone for a minute, VM Size drops to 50816K.

Textarea's value.length after running this test is 15600.

Comment 3

[Rocco Corsi]

I got this problem also when I tried to use two textareas, one as a log (same as original bug reporter) and another textarea for outputting data.

I got the problem with Firefox 3.0.7, on Vista.  On this system with 3GB of RAM, Firefox crashes after using 1.8GB of memory.

I also got the problem on XP.  On this system with 2GB of RAM , Firefox starts out using 38MB and tops out at 440MB.  I even paused the logging and it did not recover any memory.

I found a workaround where I removeChild the textarea and createElement/appendChild a new textarea with same configuration.  This seems to contain the memory leak.


I do something like this to solve the problem:

-----------------------------------------------------------------------------------------

var logtext = document.getElementById("texttest").value;

logtext = "" + hour + ":" + minute + ":" + second + " " + newlogtext + "\r\n" + logtext;

// delete current textarea node
document.getElementById("texttest_div").removeChild(document.getElementById("texttest"));

// create a new text area and set its attributes same as the original text area
var textarea_element = document.createElement("textarea");
textarea_element.id = "texttest";
textarea_element.readonly = "true";
textarea_element.rows = "20";
textarea_element.cols = "120";

textarea_element.value = logtext;

document.getElementById("texttest_div").appendChild(textarea_element);

Comment 4

[hurtsiner]

(In reply to comment #0)
Stop bothering developers with this minor problem, you are the only one, who has it

Comment 5

[Nikita Popov]

#4: If you cannot confirm the described problem, please tell us.

I tested with Minefield (latest) on Win 7.
The Memory rise was only about 4/5 MB. (I have 512 MB totally)

When setting iterations to 1000 the memory usage rose up to 52MB (from 48MB) and then did not change. After some time I closed the Firefox window, cause it took so long.

Comment 6

[Olli Pettay [:smaug]]

The testcase runs fast on trunk builds.
Is there anything which hints that there might be (still?) some memory leak?

Comment 7

[Jo Hermans]

excuses for comment 4, some is spamming various bugs, see bug 567347

Comment 8

[Firefox Bug Husbandry Bot]

https://bugzilla.mozilla.org/show_bug.cgi?id=1472046

Move all DOM bugs that haven’t been updated in more than 3 years and has no one currently assigned to P5.

If you have questions, please contact :mdaly.