Potential MySQL Buffer Problem? Need Help Debugging

From the middle of a script I've been able to isolate a (very sudden) issue with querying some data from MySQL using PHP. Using the same connection within the same API in the past, I have been able to do numerous (millions of) individual INSERT queries in the past. Also, I've been able to return and manipulate large SELECT result sets.

However, the following error has been occurring. The following returns 54265:

$status = mysql_query("SELECT * FROM Table_Name", $t_conn) or die("bad query");
echo mysql_num_rows($status);

And then, attempting the following stops at 23494:

$status = mysql_query("SELECT * FROM Table_Name", $t_conn) or die("bad query");
$i = 0;
while($dataset = mysql_fetch_assoc($status)) {
    echo $i++."<br />\n";
}

The odd thing is that it matters whether or not I am saving the fetched data. The following stops at 6494:

$status = mysql_query("SELECT * FROM Table_Name", $t_conn) or die("bad query");
$i = 0;
$dataset = array();
while($dataset[] = mysql_fetch_assoc($status)) {
    echo $i++."<br />\n";
}

This leads me to believe that I have an error with Apache or PHP. Looking at /var/log/system.log, the last line is:

Aug 17 11:43:51 zirkel com.apple.ReportCrash.Root[1862]: 2010-08-17 11:43:51.936 ReportCrash[1862:2903] Saved crash report for httpd[1263] version ??? (???) to /Library/Logs/DiagnosticReports/httpd_2010-08-17-114351_localhost.crash

Looking at the crash report yields:

Process:         httpd [1263]
Path:            /usr/local/apache2/bin/httpd
Identifier:      httpd
Version:         ??? (???)
Code Type:       X86-64 (Native)
Parent Process:  httpd [417]

Date/Time:       2010-08-17 11:43:51.006 -0600
OS Version:      Mac OS X Server 10.6.4 (10F569)
Report Version:  6

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000010
Crashed Thread:  0  Dispatch queue: com.apple.main-thread

Thread 0 Crashed:  Dispatch queue: com.apple.main-thread
0   libphp5.so                          0x00000001012abcfa mysqlnd_palloc_zval_ptr_dtor + 75 (mysqlnd_palloc.c:420)
1   libphp5.so                          0x00000001012ae74c mysqlnd_free_buffered_data + 165 (mysqlnd_result.c:216)
2   libphp5.so                          0x00000001012ae915 php_mysqlnd_res_free_result_buffers_pub + 69 (mysqlnd_result.c:340)
3   libphp5.so                          0x00000001012ae975 mysqlnd_internal_free_result_contents + 18 (mysqlnd_result.c:373)
4   libphp5.so                          0x00000001012adf7b mysqlnd_internal_free_result + 18 (mysqlnd_result.c:396)
5   libphp5.so                          0x00000001012adcf9 php_mysqlnd_res_free_result_pub + 89 (mysqlnd_result.c:1686)
6   libphp5.so                          0x00000001011456c2 _free_mysql_result + 18 (php_mysql.c:321)
7   libphp5.so                          0x000000010130ecdf list_entry_destructor + 81 (zend_list.c:184)
8   libphp5.so                          0x000000010130c048 zend_hash_apply_deleter + 198 (zend_hash.c:613)
9   libphp5.so                          0x000000010130c0f1 zend_hash_graceful_reverse_destroy + 22 (zend_hash.c:647)
10  libphp5.so                          0x00000001013012eb zend_deactivate + 188 (zend.c:899)
11  libphp5.so                          0x00000001012b5c54 php_request_shutdown + 589 (main.c:1605)
12  libphp5.so                          0x000000010137b5cd php_handler + 1373 (sapi_apache2.c:661)
13  httpd                               0x00000001000038af ap_invoke_handler + 267
14  httpd                               0x000000010002cfc3 ap_process_request + 87
15  httpd                               0x0000000100029ec8 ap_process_http_connection + 98
16  httpd                               0x000000010000cb42 ap_process_connection + 161
17  httpd                               0x0000000100045b85 child_main + 1135
18  httpd                               0x0000000100045d11 make_child + 292
19  httpd                               0x0000000100046aea ap_mpm_run + 1980
20  httpd                               0x0000000100006e52 main + 3254
21  httpd                               0x00000001000009c4 start + 52

Thread 0 crashed with X86 Thread State (64-bit):
  rax: 0x00000000ffffffff  rbx: 0x0000000101b1a3b0  rcx: 0x00007fff5fbff27f  rdx: 0x0000000000000001
  rdi: 0x0000000000000000  rsi: 0x0000000101c76280  rbp: 0x00007fff5fbff240  rsp: 0x00007fff5fbff220
   r8: 0x0000000000000001   r9: 0x0000000102a66900  r10: 0x0000000102afc0a4  r11: 0x0000000102a66690
  r12: 0x00007fff5fbff27f  r13: 0x0000000104c497e0  r14: 0x0000000101c76280  r15: 0x0000000101c76280
  rip: 0x00000001012abcfa  rfl: 0x0000000000000282  cr2: 0x0000000000000010

Binary Images:
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    0x7fff84e16000 -     0x7fff84e1bfff  libGFXShared.dylib ??? (???) <1265FAEF-1C97-B339-28A4-4510589B067B> /System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGFXShared.dylib
    0x7fff84e1c000 -     0x7fff85519067  com.apple.CoreGraphics 1.543.50 (???) <46A7D60C-0500-B96C-ECAD-1D658487D213> /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/Versions/A/CoreGraphics
    0x7fff85684000 -     0x7fff8576afe7  com.apple.DesktopServices 1.5.7 (1.5.7) <8A697128-B6CA-E4A8-C200-6520D5A35FBE> /System/Library/PrivateFrameworks/DesktopServicesPriv.framework/Versions/A/DesktopServicesPriv
    0x7fff8577f000 -     0x7fff85795fff  com.apple.ImageCapture 6.0 (6.0) <5B5AF8FB-C12A-B51F-94FC-3EC4698E818E> /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/ImageCapture.framework/Versions/A/ImageCapture
    0x7fff857ea000 -     0x7fff85ff4fe7  libBLAS.dylib 219.0.0 (compatibility 1.0.0) <FC941ECB-71D0-FAE3-DCBF-C5A619E594B8> /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib
    0x7fff86025000 -     0x7fff86028ff7  libCoreVMClient.dylib ??? (???) <DBB2C09F-4BF4-326C-B775-B7A128C501E3> /System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libCoreVMClient.dylib
    0x7fff865b7000 -     0x7fff8666cfe7  com.apple.ink.framework 1.3.3 (107) <FFC46EE0-3544-A459-2AB9-94778A75E3D4> /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/Ink.framework/Versions/A/Ink
    0x7fff86679000 -     0x7fff866b6fff  com.apple.LDAPFramework 2.0 (120.1) <16383FF5-0537-6298-73C9-473AEC9C149C> /System/Library/Frameworks/LDAP.framework/Versions/A/LDAP
    0x7fff866b7000 -     0x7fff867d0fef  libGLProgrammability.dylib ??? (???) <B057FC52-6A97-F450-48D8-325A70423A53> /System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGLProgrammability.dylib
    0x7fff867d1000 -     0x7fff8688afff  libsqlite3.dylib 9.6.0 (compatibility 9.0.0) <5A15E12A-AE8F-1A36-BBC7-564E7D7AD0FB> /usr/lib/libsqlite3.dylib
    0x7fff8688b000 -     0x7fff86b0cfef  com.apple.Foundation 6.6.3 (751.29) <DAEDB589-9F59-9556-CF8D-07556317937B> /System/Library/Frameworks/Foundation.framework/Versions/C/Foundation
    0x7fff86b62000 -     0x7fff86be1fef  com.apple.audio.CoreAudio 3.2.2 (3.2.2) <243E456E-7A74-BE76-FF18-E589BDCAA785> /System/Library/Frameworks/CoreAudio.framework/Versions/A/CoreAudio
    0x7fff86be4000 -     0x7fff87027fef  libLAPACK.dylib 219.0.0 (compatibility 1.0.0) <0CC61C98-FF51-67B3-F3D8-C5E430C201A9> /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libLAPACK.dylib
    0x7fff8703a000 -     0x7fff8703bff7  com.apple.audio.units.AudioUnit 1.6.3 (1.6.3) <D4183AC4-8A65-8368-A9AF-E2A13D18519C> /System/Library/Frameworks/AudioUnit.framework/Versions/A/AudioUnit
    0x7fff870bf000 -     0x7fff870f7fef  libcups.2.dylib 2.8.0 (compatibility 2.0.0) <31A78904-A500-0DA9-0609-F1EB81383326> /usr/lib/libcups.2.dylib
    0x7fff870f8000 -     0x7fff87184fef  SecurityFoundation ??? (???) <6860DE26-0D42-D1E8-CD7C-5B42D78C1E1D> /System/Library/Frameworks/SecurityFoundation.framework/Versions/A/SecurityFoundation
    0x7fff87185000 -     0x7fff872faff7  com.apple.CoreFoundation 6.6.3 (550.29) <48810602-63C3-994D-E563-DD02B16E76E1> /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation
    0x7fff872fb000 -     0x7fff8731dff7  libexpat.1.dylib 7.2.0 (compatibility 7.0.0) <8EC31253-B585-D05E-F35D-AE3292FB790B> /usr/lib/libexpat.1.dylib
    0x7fff8731e000 -     0x7fff873d3fe7  com.apple.ColorSync 4.6.3 (4.6.3) <AA93AD96-6974-9104-BF55-AF7A813C8A1B> /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/ColorSync.framework/Versions/A/ColorSync
    0x7fff873dd000 -     0x7fff873e3ff7  com.apple.DiskArbitration 2.3 (2.3) <857F6E43-1EF4-7D53-351B-10DE0A8F992A> /System/Library/Frameworks/DiskArbitration.framework/Versions/A/DiskArbitration
    0x7fff873e4000 -     0x7fff874beff7  com.apple.vImage 4.0 (4.0) <354F34BF-B221-A3C9-2CA7-9BE5E14AD5AD> /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vImage.framework/Versions/A/vImage
    0x7fff874bf000 -     0x7fff875b7ff7  libiconv.2.dylib 7.0.0 (compatibility 7.0.0) <7E4ADB5A-CC77-DCFD-3E54-2F35A2C8D95A> /usr/lib/libiconv.2.dylib
    0x7fff87764000 -     0x7fff87773fff  com.apple.NetFS 3.2.1 (3.2.1) <FF21DB1E-F425-1005-FB70-BC19CAF4006E> /System/Library/Frameworks/NetFS.framework/Versions/A/NetFS
    0x7fff878e7000 -     0x7fff87c1afe7  com.apple.CoreServices.CarbonCore 861.13 (861.13) <BC2F9B4E-D305-D717-D97E-EC78C7DE9EE9> /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/CarbonCore.framework/Versions/A/CarbonCore
    0x7fff8802c000 -     0x7fff8802cff7  com.apple.ApplicationServices 38 (38) <10A0B9E9-4988-03D4-FC56-DDE231A02C63> /System/Library/Frameworks/ApplicationServices.framework/Versions/A/ApplicationServices
    0x7fff88151000 -     0x7fff88311fef  libSystem.B.dylib 125.2.0 (compatibility 1.0.0) <95E02DD0-ADEA-745B-E7FA-ABA064E4658C> /usr/lib/libSystem.B.dylib
    0x7fff88312000 -     0x7fff8833afff  com.apple.DictionaryServices 1.1.1 (1.1.1) <9FD709FC-23F0-F270-EAC1-C590CD516A36> /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/DictionaryServices.framework/Versions/A/DictionaryServices
    0x7fff8833b000 -     0x7fff88377fe7  libcurl.4.dylib 6.1.0 (compatibility 6.0.0) <1E041185-131C-C237-C250-38BE933A269A> /usr/lib/libcurl.4.dylib
    0x7fff883b7000 -     0x7fff883c3fff  libbz2.1.0.dylib 1.0.5 (compatibility 1.0.0) <5C876577-ACB7-020C-F7DB-EE0135C3AB8D> /usr/lib/libbz2.1.0.dylib
    0x7fff883c4000 -     0x7fff8864aff7  com.apple.security 6.1.1 (37594) <5EDDC08C-C95B-2D24-E1D2-D30D233AB065> /System/Library/Frameworks/Security.framework/Versions/A/Security
    0x7fff88724000 -     0x7fff88775fe7  com.apple.HIServices 1.8.0 (???) <1ABA7802-C1E4-06A0-9035-2792CC915BF6> /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/HIServices.framework/Versions/A/HIServices
    0x7fff88782000 -     0x7fff8883fff7  com.apple.CoreServices.OSServices 357 (357) <718F0719-DC9F-E392-7C64-9D7DFE3D02E2> /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/OSServices.framework/Versions/A/OSServices
    0x7fff88a7c000 -     0x7fff88a7cff7  com.apple.Accelerate.vecLib 3.6 (vecLib 3.6) <DA9BFF01-40DF-EBD5-ABB7-787DAF2D77CF> /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/vecLib
    0x7fff88a7d000 -     0x7fff88a92ff7  com.apple.LangAnalysis 1.6.6 (1.6.6) <DC999B32-BF41-94C8-0583-27D9AB463E8B> /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/LangAnalysis.framework/Versions/A/LangAnalysis
    0x7fff88a93000 -     0x7fff88ab8fe7  com.apple.CoreVideo 1.6.1 (45.4) <B1516554-88BC-CF1E-5409-BFF27A73D1AF> /System/Library/Frameworks/CoreVideo.framework/Versions/A/CoreVideo
    0x7fff88ab9000 -     0x7fff88adffe7  libJPEG.dylib ??? (???) <4060F3E2-BAD3-244F-D777-51BA16569DA4> /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/ImageIO.framework/Versions/A/Resources/libJPEG.dylib
    0x7fff88ae0000 -     0x7fff88b5efff  com.apple.CoreText 3.1.0 (???) <B740DA1D-EFD0-CCBF-F893-E3004FE58A98> /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreText.framework/Versions/A/CoreText
    0x7fff88b5f000 -     0x7fff88b6eff7  com.apple.opengl 1.6.8 (1.6.8) <0CDC4F98-7981-A114-1778-AF171075138E> /System/Library/Frameworks/OpenGL.framework/Versions/A/OpenGL
    0x7fff88b6f000 -     0x7fff88b8aff7  com.apple.openscripting 1.3.1 (???) <FD46A0FE-AC79-3EF7-AB4F-396D376DDE71> /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/OpenScripting.framework/Versions/A/OpenScripting
    0x7fff88b8b000 -     0x7fff88b8dfff  libRadiance.dylib ??? (???) <D67C08B6-4D4A-916D-E936-528E145A56E2> /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/ImageIO.framework/Versions/A/Resources/libRadiance.dylib
    0x7fff88b8e000 -     0x7fff88bd7fef  libGLU.dylib ??? (???) <34D118CD-F9EE-D023-FEBF-74581DEF31CD> /System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGLU.dylib
    0x7fff88cf5000 -     0x7fff88ff3fe7  com.apple.HIToolbox 1.6.3 (???) <CF0C8524-FA82-3908-ACD0-A9176C704AED> /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/HIToolbox
    0x7fffffe00000 -     0x7fffffe01fff  libSystem.B.dylib ??? (???) <95E02DD0-ADEA-745B-E7FA-ABA064E4658C> /usr/lib/libSystem.B.dylib

Help debugging the problem is appreciated.

Best, Mark

A hint from ircmaxell led me to execute the script from the command line. While error_reporting(E_ALL); was indeed on, the error wasn't displayed through apache. But, from the command line I received:

PHP Fatal error:  Allowed memory size of 268435456 bytes exhausted (tried to allocate 2048 bytes)

While 256M is already a pretty large amount of memory, at least I have a lead to go on and will try splitting up the task.