Re: OT: (Way OT) PHP and MySQL concurrency control using MyISAM tables
In response to Da Rock [EMAIL PROTECTED]: [massive snip] I remember now exactly why I wanted MyISAM- you see the table locking is exactly what I need for the task. I just need to come up with a method to ensure what I send to the server does actually get written- or am I just being paranoid? The task I require needs to offer direct sequential access with no undoing of written data. And given the legality of the task based on these strict requirements, you can understand my paranoia. Sounds to me that you want something more like a logfile, where you can write a line of data, then fsync the file to guarantee that it's been committed to disk. Of course, depending on how you'll need to access this data later, this may not be the best approach. I don't know the details of how MySQL does or does not guarantee that your data is safely on disk, but I can say that PostgreSQL uses fsync after each commit to ensure you're data can not be lost. From there, it's up to the hardware, so ensure you have quality disks that don't lie about caching, and you'll probably want a battery-backed RAID controller and some sort of disk redundancy (i.e. RAID-10) -- Bill Moran http://www.potentialtech.com ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: OT: (Way OT) PHP and MySQL concurrency control using MyISAM tables
On Sun, 2008-03-23 at 17:01 -0700, Patrick C wrote: MyISAM supports locking (like all engines) but not transactions. Without transactions, you can do a lock lock a table or tables, and unlock them, however you cannot roll back statements -- so if a statement down the line fails for some reason there is no way to rollback and undo past statements (automagically at least) The simple solution is to use InnoDB, which supports Good Things you want - it's more scalable across multiple threads, row-level locking, transactions, foreign keys, etc. The differences are fairly well documented. It sounds like you're using PDO, please read up on auto-commit mode. Don't reinvent the wheel, especially when the wheel is already built better than you could hack out a replacement for it :) -Patrick On 23/03/2008, Da Rock [EMAIL PROTECTED] wrote: On Sun, 2008-03-23 at 19:17 -0400, Bill Moran wrote: Da Rock [EMAIL PROTECTED] wrote: I know this is not quite the list for these things, but I tried the PHP list and got no reply whatsoever. In fact, I don't think anyone's home cause the entire list is silent... I'm trying to setup a system using web apps in PHP using MySQL as the backend database, only this time I need transaction services. According to the PHP manual if a transaction is served for MySQL it can come back as committed even though it may not. So what I'm trying to accomplish is develop some row level locking with the PHP script. I enquired about setting up a servlet (for want of a better term) with PHP, something that will serve the requests of the rest of the app. To be honest though, I'm not entirely sure how to approach this. Wow. That's one crazy attempt at a workaround. The correct solution is to use the correct tool for the job. Either install PostgreSQL and use it instead, or use InnoDB tables. Actually, I think I may have got some facts confused here- I thought that MyISAM was not supposed to be transaction supported, but according to most stuff I've read it supports table level transaction locking. And the PHP manual says it will only come back with a false commit IF the table DOESN'T support transactions at all. So what is the truth here? If MyISAM supports transaction table locking I may be ok here- and save myself a hell of a lot of trouble to boot. Thanks guys, again. I remember now exactly why I wanted MyISAM- you see the table locking is exactly what I need for the task. I just need to come up with a method to ensure what I send to the server does actually get written- or am I just being paranoid? The task I require needs to offer direct sequential access with no undoing of written data. And given the legality of the task based on these strict requirements, you can understand my paranoia. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: OT: (Way OT) PHP and MySQL concurrency control using MyISAM tables
Da Rock [EMAIL PROTECTED] wrote: I know this is not quite the list for these things, but I tried the PHP list and got no reply whatsoever. In fact, I don't think anyone's home cause the entire list is silent... I'm trying to setup a system using web apps in PHP using MySQL as the backend database, only this time I need transaction services. According to the PHP manual if a transaction is served for MySQL it can come back as committed even though it may not. So what I'm trying to accomplish is develop some row level locking with the PHP script. I enquired about setting up a servlet (for want of a better term) with PHP, something that will serve the requests of the rest of the app. To be honest though, I'm not entirely sure how to approach this. Wow. That's one crazy attempt at a workaround. The correct solution is to use the correct tool for the job. Either install PostgreSQL and use it instead, or use InnoDB tables. -- Bill Moran http://www.potentialtech.com ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: OT: (Way OT) PHP and MySQL concurrency control using MyISAM tables
On Sun, 2008-03-23 at 19:17 -0400, Bill Moran wrote: Da Rock [EMAIL PROTECTED] wrote: I know this is not quite the list for these things, but I tried the PHP list and got no reply whatsoever. In fact, I don't think anyone's home cause the entire list is silent... I'm trying to setup a system using web apps in PHP using MySQL as the backend database, only this time I need transaction services. According to the PHP manual if a transaction is served for MySQL it can come back as committed even though it may not. So what I'm trying to accomplish is develop some row level locking with the PHP script. I enquired about setting up a servlet (for want of a better term) with PHP, something that will serve the requests of the rest of the app. To be honest though, I'm not entirely sure how to approach this. Wow. That's one crazy attempt at a workaround. The correct solution is to use the correct tool for the job. Either install PostgreSQL and use it instead, or use InnoDB tables. Actually, I think I may have got some facts confused here- I thought that MyISAM was not supposed to be transaction supported, but according to most stuff I've read it supports table level transaction locking. And the PHP manual says it will only come back with a false commit IF the table DOESN'T support transactions at all. So what is the truth here? If MyISAM supports transaction table locking I may be ok here- and save myself a hell of a lot of trouble to boot. Thanks guys, again. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: OT: (Way OT) PHP and MySQL concurrency control using MyISAM tables
MyISAM supports locking (like all engines) but not transactions. Without transactions, you can do a lock lock a table or tables, and unlock them, however you cannot roll back statements -- so if a statement down the line fails for some reason there is no way to rollback and undo past statements (automagically at least) The simple solution is to use InnoDB, which supports Good Things you want - it's more scalable across multiple threads, row-level locking, transactions, foreign keys, etc. The differences are fairly well documented. It sounds like you're using PDO, please read up on auto-commit mode. Don't reinvent the wheel, especially when the wheel is already built better than you could hack out a replacement for it :) -Patrick On 23/03/2008, Da Rock [EMAIL PROTECTED] wrote: On Sun, 2008-03-23 at 19:17 -0400, Bill Moran wrote: Da Rock [EMAIL PROTECTED] wrote: I know this is not quite the list for these things, but I tried the PHP list and got no reply whatsoever. In fact, I don't think anyone's home cause the entire list is silent... I'm trying to setup a system using web apps in PHP using MySQL as the backend database, only this time I need transaction services. According to the PHP manual if a transaction is served for MySQL it can come back as committed even though it may not. So what I'm trying to accomplish is develop some row level locking with the PHP script. I enquired about setting up a servlet (for want of a better term) with PHP, something that will serve the requests of the rest of the app. To be honest though, I'm not entirely sure how to approach this. Wow. That's one crazy attempt at a workaround. The correct solution is to use the correct tool for the job. Either install PostgreSQL and use it instead, or use InnoDB tables. Actually, I think I may have got some facts confused here- I thought that MyISAM was not supposed to be transaction supported, but according to most stuff I've read it supports table level transaction locking. And the PHP manual says it will only come back with a false commit IF the table DOESN'T support transactions at all. So what is the truth here? If MyISAM supports transaction table locking I may be ok here- and save myself a hell of a lot of trouble to boot. Thanks guys, again. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED] ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: OT: (Way OT) PHP and MySQL concurrency control using MyISAM tables
--On March 24, 2008 9:03:35 AM +1000 Da Rock [EMAIL PROTECTED] wrote: I know this is not quite the list for these things, but I tried the PHP list and got no reply whatsoever. In fact, I don't think anyone's home cause the entire list is silent... I'm trying to setup a system using web apps in PHP using MySQL as the backend database, only this time I need transaction services. According to the PHP manual if a transaction is served for MySQL it can come back as committed even though it may not. So what I'm trying to accomplish is develop some row level locking with the PHP script. I enquired about setting up a servlet (for want of a better term) with PHP, something that will serve the requests of the rest of the app. To be honest though, I'm not entirely sure how to approach this. Any ideas would be very welcome. Following list etiquette, I'm replying to you and the list. I believe that postgresql has transaction locking. You might consider using it instead. Mysql is supposed to have transaction locking in version 5.1, but I haven't tested it and don't know how robust it is. Paul Schmehl ([EMAIL PROTECTED]) Senior Information Security Analyst The University of Texas at Dallas http://www.utdallas.edu/ir/security/ ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
