#33070 [Opn->Fbk]: bzdecompress inefficient

ID: 33070 Updated by: tony2001@php.net Reported By: lindsay at bitleap dot com -Status: Open +Status: Feedback Bug Type: Performance problem Operating System: Linux 2.6.10 kernel PHP Version: 5.0.3 New Comment: Please provide a short but complete reproduce script and (if possible) the data too. Previous Comments: ------------------------------------------------------------------------ [2005-05-19 17:22:47] lindsay at bitleap dot com Description: ------------ I found bug #13860 regarding bzdecompress speeds on 4.2.x. The bug suggests its fixed for 4.2.0 but I see slowness in 5.0.3. On 5.0.3, bzdecompress seems to get exponentionally slower as data sizes increase. I timed the length of decompression on increasing file sizes containing compressed random data: file length 256K ran in: 2 seconds file length 512K ran in: 10 seconds file length 1M ran in: 41 seconds file length 2M ran in: 135 seconds file length 3M ran in: 278 seconds file length 4M ran in: 476 seconds I'm not a c coder but the do while loop at line 472 of: http://cvs.php.net/co.php/php-src/ext/bz2/bz2.c?r=1.9 seems to decompress the string over and over. Each iteration attempts a decompress w/ a buffer size based on the iteration count. If the decompress fails, a larger buffer is tried. If I'm reading this correctly, the same data could be decompressed hundreds of times until the buffer gets large enough. ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=33070&edit=1