Re: [PHP] PHP 4.3.10 and Apache2.0 with MPM
[EMAIL PROTECTED] wrote: > When I install PHP 4.3.10 with Apache 2.0 with a tool called YUM that > installs rpms for Fedora Core 3 I get the following: > > Apache is running a threaded MPM, but your PHP Module is not compiled to > be > threadsafe. You need to recompile PHP. Pre-configuration failed > > I¹m not sure why Fedora would distribute a package that wouldn¹t work with > other packages, however what is this threadsafe¹ feature and how can I > specifically enable it so I can get php installed? "Threads" are, crudely put, allowing a program to "clone" itself and run multiple copies of itself at one time, sharing some data among the various threads in the strand of program execution, but mostly having each thread running independently. Some perfectly good programs were written with no intent to ever run in a threaded environment. Such programs might, or might not, handle data in a way that, if they *ARE* run in a threaded environment, will crash the computer very very very nastily. Consider this PHP script, for example: \n"; return $foo; } ?> It just keeps a counter going throughout program execution. But what happens when, suddenly, *TWO* threads are running that same function AT ONE TIME. Whammo! They *both* try to alter $foo, and they are both expecting $foo to increase by 1 in each function call, but the *other* thread is messing with $foo, and $foo is *NOT* gonna behave the way they expect. So, either *ALL* your programs that get compiled together have to be thread-safe, or *none* of them should use threads. You chose an Apache that was specifically compiled to use threads. That has certain advantages. It also has the disadvantage that all the Apache Modules you use, and any sub-Module of those Modules, must all be specifically compiled to use threads. More importantly, all that software has to have been specially programmed, tested, and re-tested, to be *SURE* it's not doing something that will crash under threads. Your PHP was not compiled with threads. You can either re-compile/download an Apache2 that doesn't use threads, or re-compile/download a PHP and all its Modules to use threads. WARNING: Just because you can COMPILE with threads "on" doesn't mean that anybody has thoroughly tested and debugged the Module you compiled with threads "on" You may be creating a disaster waiting to happen. It will frequently not even manifest for a lonnnggg time until two threads just *HAPPEN* to "do something" that wasn't thread safe. It could be a few minutes, a few days, a few months, or even a few years before that happens. It's all a matter of probabiliy and which functions are getting called when by the program whether or not something like my example function above will happen. Your safest bet is to back off from the threads version of Apache 2, and stick with non-threaded software. Your second option is to try the thread stuff, but test the hell out of it before you put it on a "real" site where you care if it crashes or not. Some people want threads. Some would rather be safer. RedHat has to cater to both groups. -- Like Music? http://l-i-e.com/artists.htm -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] PHP 4.3.10 and Apache2.0 with MPM
[EMAIL PROTECTED] wrote: > When I install PHP 4.3.10 with Apache 2.0 with a tool called YUM that > installs rpms for Fedora Core 3 I get the following: > > Apache is running a threaded MPM, but your PHP Module is not compiled to > be > threadsafe. You need to recompile PHP. Pre-configuration failed > > I¹m not sure why Fedora would distribute a package that wouldn¹t work with > other packages, however what is this threadsafe¹ feature and how can I > specifically enable it so I can get php installed? "Threads" are, crudely put, allowing a program to "clone" itself and run multiple copies of itself at one time, sharing some data among the various threads in the strand of program execution, but mostly having each thread running independently. Some perfectly good programs were written with no intent to ever run in a threaded environment. Such programs might, or might not, handle data in a way that, if they *ARE* run in a threaded environment, will crash the computer very very very nastily. Consider this PHP script, for example: \n"; return $foo; } ?> It just keeps a counter going throughout program execution. But what happens when, suddenly, *TWO* threads are running that same function AT ONE TIME. Whammo! They *both* try to alter $foo, and they are both expecting $foo to increase by 1 in each function call, but the *other* thread is messing with $foo, and $foo is *NOT* gonna behave the way they expect. So, either *ALL* your programs that get compiled together have to be thread-safe, or *none* of them should use threads. You chose an Apache that was specifically compiled to use threads. That has certain advantages. It also has the disadvantage that all the Apache Modules you use, and any sub-Module of those Modules, must all be specifically compiled to use threads. More importantly, all that software has to have been specially programmed, tested, and re-tested, to be *SURE* it's not doing something that will crash under threads. Your PHP was not compiled with threads. You can either re-compile/download an Apache2 that doesn't use threads, or re-compile/download a PHP and all its Modules to use threads. WARNING: Just because you can COMPILE with threads "on" doesn't mean that anybody has thoroughly tested and debugged the Module you compiled with threads "on" You may be creating a disaster waiting to happen. It will frequently not even manifest for a lonnnggg time until two threads just *HAPPEN* to "do something" that wasn't thread safe. It could be a few minutes, a few days, a few months, or even a few years before that happens. It's all a matter of probabiliy and which functions are getting called when by the program whether or not something like my example function above will happen. Your safest bet is to back off from the threads version of Apache 2, and stick with non-threaded software. Your second option is to try the thread stuff, but test the hell out of it before you put it on a "real" site where you care if it crashes or not. Some people want threads. Some would rather be safer. RedHat has to cater to both groups. -- Like Music? http://l-i-e.com/artists.htm -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] PHP 4.3.10 and Apache2.0 with MPM
[EMAIL PROTECTED] wrote: > When I install PHP 4.3.10 with Apache 2.0 with a tool called YUM that > installs rpms for Fedora Core 3 I get the following: > > Apache is running a threaded MPM, but your PHP Module is not compiled to > be > threadsafe. You need to recompile PHP. Pre-configuration failed > > I¹m not sure why Fedora would distribute a package that wouldn¹t work with > other packages, however what is this threadsafe¹ feature and how can I > specifically enable it so I can get php installed? "Threads" are, crudely put, allowing a program to "clone" itself and run multiple copies of itself at one time, sharing some data among the various threads in the strand of program execution, but mostly having each thread running independently. Some perfectly good programs were written with no intent to ever run in a threaded environment. Such programs might, or might not, handle data in a way that, if they *ARE* run in a threaded environment, will crash the computer very very very nastily. Consider this PHP script, for example: \n"; return $foo; } ?> It just keeps a counter going throughout program execution. But what happens when, suddenly, *TWO* threads are running that same function AT ONE TIME. Whammo! They *both* try to alter $foo, and they are both expecting $foo to increase by 1 in each function call, but the *other* thread is messing with $foo, and $foo is *NOT* gonna behave the way they expect. So, either *ALL* your programs that get compiled together have to be thread-safe, or *none* of them should use threads. You chose an Apache that was specifically compiled to use threads. That has certain advantages. It also has the disadvantage that all the Apache Modules you use, and any sub-Module of those Modules, must all be specifically compiled to use threads. More importantly, all that software has to have been specially programmed, tested, and re-tested, to be *SURE* it's not doing something that will crash under threads. Your PHP was not compiled with threads. You can either re-compile/download an Apache2 that doesn't use threads, or re-compile/download a PHP and all its Modules to use threads. WARNING: Just because you can COMPILE with threads "on" doesn't mean that anybody has thoroughly tested and debugged the Module you compiled with threads "on" You may be creating a disaster waiting to happen. It will frequently not even manifest for a lonnnggg time until two threads just *HAPPEN* to "do something" that wasn't thread safe. It could be a few minutes, a few days, a few months, or even a few years before that happens. It's all a matter of probabiliy and which functions are getting called when by the program whether or not something like my example function above will happen. Your safest bet is to back off from the threads version of Apache 2, and stick with non-threaded software. Your second option is to try the thread stuff, but test the hell out of it before you put it on a "real" site where you care if it crashes or not. Some people want threads. Some would rather be safer. RedHat has to cater to both groups. -- Like Music? http://l-i-e.com/artists.htm -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] PHP 4.3.10 and Apache2.0 with MPM
[EMAIL PROTECTED] wrote: > When I install PHP 4.3.10 with Apache 2.0 with a tool called YUM that > installs rpms for Fedora Core 3 I get the following: > > Apache is running a threaded MPM, but your PHP Module is not compiled to > be > threadsafe. You need to recompile PHP. Pre-configuration failed > > I¹m not sure why Fedora would distribute a package that wouldn¹t work with > other packages, however what is this threadsafe¹ feature and how can I > specifically enable it so I can get php installed? "Threads" are, crudely put, allowing a program to "clone" itself and run multiple copies of itself at one time, sharing some data among the various threads in the strand of program execution, but mostly having each thread running independently. Some perfectly good programs were written with no intent to ever run in a threaded environment. Such programs might, or might not, handle data in a way that, if they *ARE* run in a threaded environment, will crash the computer very very very nastily. Consider this PHP script, for example: \n"; return $foo; } ?> It just keeps a counter going throughout program execution. But what happens when, suddenly, *TWO* threads are running that same function AT ONE TIME. Whammo! They *both* try to alter $foo, and they are both expecting $foo to increase by 1 in each function call, but the *other* thread is messing with $foo, and $foo is *NOT* gonna behave the way they expect. So, either *ALL* your programs that get compiled together have to be thread-safe, or *none* of them should use threads. You chose an Apache that was specifically compiled to use threads. That has certain advantages. It also has the disadvantage that all the Apache Modules you use, and any sub-Module of those Modules, must all be specifically compiled to use threads. More importantly, all that software has to have been specially programmed, tested, and re-tested, to be *SURE* it's not doing something that will crash under threads. Your PHP was not compiled with threads. You can either re-compile/download an Apache2 that doesn't use threads, or re-compile/download a PHP and all its Modules to use threads. WARNING: Just because you can COMPILE with threads "on" doesn't mean that anybody has thoroughly tested and debugged the Module you compiled with threads "on" You may be creating a disaster waiting to happen. It will frequently not even manifest for a lonnnggg time until two threads just *HAPPEN* to "do something" that wasn't thread safe. It could be a few minutes, a few days, a few months, or even a few years before that happens. It's all a matter of probabiliy and which functions are getting called when by the program whether or not something like my example function above will happen. Your safest bet is to back off from the threads version of Apache 2, and stick with non-threaded software. Your second option is to try the thread stuff, but test the hell out of it before you put it on a "real" site where you care if it crashes or not. Some people want threads. Some would rather be safer. RedHat has to cater to both groups. -- Like Music? http://l-i-e.com/artists.htm -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] PHP 4.3.10 and Apache2.0 with MPM
[EMAIL PROTECTED] wrote: > When I install PHP 4.3.10 with Apache 2.0 with a tool called YUM that > installs rpms for Fedora Core 3 I get the following: > > Apache is running a threaded MPM, but your PHP Module is not compiled to > be > threadsafe. You need to recompile PHP. Pre-configuration failed > > I¹m not sure why Fedora would distribute a package that wouldn¹t work with > other packages, however what is this threadsafe¹ feature and how can I > specifically enable it so I can get php installed? "Threads" are, crudely put, allowing a program to "clone" itself and run multiple copies of itself at one time, sharing some data among the various threads in the strand of program execution, but mostly having each thread running independently. Some perfectly good programs were written with no intent to ever run in a threaded environment. Such programs might, or might not, handle data in a way that, if they *ARE* run in a threaded environment, will crash the computer very very very nastily. Consider this PHP script, for example: \n"; return $foo; } ?> It just keeps a counter going throughout program execution. But what happens when, suddenly, *TWO* threads are running that same function AT ONE TIME. Whammo! They *both* try to alter $foo, and they are both expecting $foo to increase by 1 in each function call, but the *other* thread is messing with $foo, and $foo is *NOT* gonna behave the way they expect. So, either *ALL* your programs that get compiled together have to be thread-safe, or *none* of them should use threads. You chose an Apache that was specifically compiled to use threads. That has certain advantages. It also has the disadvantage that all the Apache Modules you use, and any sub-Module of those Modules, must all be specifically compiled to use threads. More importantly, all that software has to have been specially programmed, tested, and re-tested, to be *SURE* it's not doing something that will crash under threads. Your PHP was not compiled with threads. You can either re-compile/download an Apache2 that doesn't use threads, or re-compile/download a PHP and all its Modules to use threads. WARNING: Just because you can COMPILE with threads "on" doesn't mean that anybody has thoroughly tested and debugged the Module you compiled with threads "on" You may be creating a disaster waiting to happen. It will frequently not even manifest for a lonnnggg time until two threads just *HAPPEN* to "do something" that wasn't thread safe. It could be a few minutes, a few days, a few months, or even a few years before that happens. It's all a matter of probabiliy and which functions are getting called when by the program whether or not something like my example function above will happen. Your safest bet is to back off from the threads version of Apache 2, and stick with non-threaded software. Your second option is to try the thread stuff, but test the hell out of it before you put it on a "real" site where you care if it crashes or not. Some people want threads. Some would rather be safer. RedHat has to cater to both groups. -- Like Music? http://l-i-e.com/artists.htm -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
