#27176 [NEW]: str_replace tries to use obscene amounts of ram

From: gaz at fission dot org dot uk Operating system: Slackware 9.1 Linux 2.6.1 kernel PHP version: 5.0.0b3 (beta3) PHP Bug Type: Performance problem Bug description: str_replace tries to use obscene amounts of ram Description: ------------ When str_replace is called with the 'mixed replace' value set to a string with a large (eg, 16,000) characters in it, it suddenly tries to asign an absolutly obscene amount of memory. Reproduce code: --------------- /* In the code that initially showed this up, $somefile was a 20kb html file, and $replacefile was a 6kb html file */ $input_text = file_get_contents($somefile); $replace = file_get_contents($replacefile); $match = "__RECENT__"; $output = str_replace($match,$replce,$input_text); Actual result: -------------- The actual code tries to allocate about 34MB of memory to do this str_replace. I think it keeps trying to reorder the char[] array, and so a large replacement string ties it up for a while. Changing to use explode() and foreach() tends to do the same thing but in no time, and without the huge memory tie-up. -- Edit bug report at http://bugs.php.net/?id=27176&edit=1 -- Try a CVS snapshot (php4): http://bugs.php.net/fix.php?id=27176&r=trysnapshot4 Try a CVS snapshot (php5): http://bugs.php.net/fix.php?id=27176&r=trysnapshot5 Fixed in CVS: http://bugs.php.net/fix.php?id=27176&r=fixedcvs Fixed in release: http://bugs.php.net/fix.php?id=27176&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=27176&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=27176&r=needscript Try newer version: http://bugs.php.net/fix.php?id=27176&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=27176&r=support Expected behavior: http://bugs.php.net/fix.php?id=27176&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=27176&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=27176&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=27176&r=globals PHP 3 support discontinued: http://bugs.php.net/fix.php?id=27176&r=php3 Daylight Savings: http://bugs.php.net/fix.php?id=27176&r=dst IIS Stability: http://bugs.php.net/fix.php?id=27176&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=27176&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=27176&r=float