[Lift] Re: Multi-Database Transactions
As Jeppe says, I'm avoiding XA.. This is because when we tried it in a Java project, we had a problem where connections were dropped over time and no new ones could be created. Luckily this never got past our test system. We were unable to recreate it and so could never verify any fix. After that, we decided not to rely on any transaction 'magic'. If it's broke, we need to be able to fix it ourselves. Our requirements are pretty simple, so I think we can do what was suggested here, and add any addidional logic ourselves. Anything crossing both DBs would be stats related, and so losing the occasional row would not be an issue. On Dec 9, 1:56 pm, David Pollak feeder.of.the.be...@gmail.com wrote: On Wed, Dec 9, 2009 at 12:09 AM, Jeppe Nejsum Madsen je...@ingolfs.dkwrote: On Wed, Dec 9, 2009 at 5:05 AM, David Pollak feeder.of.the.be...@gmail.com wrote: I think what you want is the Lift JTA module: http://github.com/dpp/liftweb/tree/master/lift-modules/lift-jta/ I think the OP wanted to avoid XA transactions. But of course, if data integriity is important this is the right way to go. I haven't looked at lift-jta. Does it provide something else besides hooking into JTA that would be useful in this scenario? Dunno... it's Jonas's brainchild. ;-) /Jeppe -- You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to lift...@googlegroups.com. To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.comliftweb%2bunsubscr...@googlegroups.com . For more options, visit this group at http://groups.google.com/group/liftweb?hl=en. -- Lift, the simply functional web frameworkhttp://liftweb.net Beginning Scalahttp://www.apress.com/book/view/1430219890 Follow me:http://twitter.com/dpp Surf the harmonics -- You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to lift...@googlegroups.com. To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/liftweb?hl=en.
[Lift] Re: Multi-Database Transactions
Hi Jeppe - thanks for your response.
So, am I correct in saying that I just need to do something like
this? (not tested code - just an approximation)
//Assuming fooDb and barDb are some form of connection wrapper...
S.addAround(List(new LoanWrapper {
def apply[T](f: = T): T = {
fooDb.begin
barDb.begin
try {
val result = f
barDb.commit
fooDb.commit
result
}
catch {
case e = {
barDb.rollback
fooDb.rollback
}
}
}
}))
On Dec 2, 11:56 am, Jeppe Nejsum Madsen je...@ingolfs.dk wrote:
deadfolk deadf...@gmail.com writes:
[...]
I'll likely be using plain JDBC or JPA. What would be my options in
Lift? Can I get a list of connections and just use a filter (or
equivalent) to begin/commit/rollback on each within every request?
I've done some searching, but I've not found anything relating to the
use of multiple databases.
Any advice/pointers would be very much appreciated.
Lift already supports wrapping the request with code. e.g I have
S.addAround(DB.buildLoanWrapper)
in Boot.scala which wraps a transaction around the request.
I haven't tried multiple databases, but it should be trivial (famous
last words :-) to extend this to also work in this scenario (when you
don't want XA transactions)
This is for Mapper, the Lift ORM, I assume JPA can be made to work in
similar ways...
/Jeppe
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[Lift] Re: JSON Reponses
Wow - thanks for the reponses, guys! Plenty to look at here. Doesn't look like I should be concerned about support for Lift. If only some of the commercial support contracts we have were as helpful. On Dec 3, 7:17 pm, Ross Mellgren dri...@gmail.com wrote: Views are for providing template XML, I believe, and so are still using NodeSeq and wouldn't address the problem. Looking at the type of LiftRules.viewDispatch seems to imply that, at least. -Ross On Dec 3, 2009, at 1:59 PM, Daniel Nelson wrote: Hi Matt, I'm pretty new/novice myself, but I believe you do this through View instead of Snippet. Don't forget to add the specific View page to Sitemap otherwise it won't be accessible when you call it. Hope this is accurate / helpful. Dan On Dec 3, 11:06 am, deadfolk deadf...@gmail.com wrote: Hi all, I'm still at the evaluation stage of Lift, so please forgive my ignorance, but I cannot figure out how to render any non-XML reponses. I'm looking to create a simple web service which can send reponses back in either XML or JSON. I have the XML side covered, but I can't figure out how to send a JSON response back. Snippets take a NodeSeq and return a NodeSeq, so unless I'm missing something here, they are only good for XML. I've found various posts on JSON, but they all seem to relate to forms and AJAX, whereas all I really want to be able to do is render JSON instead of XML. Any pointers greatly appreciated, Matt -- You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to lift...@googlegroups.com. To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com . For more options, visit this group athttp://groups.google.com/group/liftweb?hl=en . -- You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to lift...@googlegroups.com. To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/liftweb?hl=en.
[Lift] JSON Reponses
Hi all, I'm still at the evaluation stage of Lift, so please forgive my ignorance, but I cannot figure out how to render any non-XML reponses. I'm looking to create a simple web service which can send reponses back in either XML or JSON. I have the XML side covered, but I can't figure out how to send a JSON response back. Snippets take a NodeSeq and return a NodeSeq, so unless I'm missing something here, they are only good for XML. I've found various posts on JSON, but they all seem to relate to forms and AJAX, whereas all I really want to be able to do is render JSON instead of XML. Any pointers greatly appreciated, Matt -- You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to lift...@googlegroups.com. To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/liftweb?hl=en.
[Lift] Multi-Database Transactions
Hi all, I'm currently evaluating Lift for a new project I'll be working on soon, and I'm looking for a little input regarding if/how I can manage transactions across two databases. It's going to be a bunch of web services over two MySQL databases. I'll need to synchronize transactions across the two, but I won't be using XA, as we've had some problems in this area. I don't know if it's us, drivers, JBoss, MySQL server itself or what, but we're steering clear regardless, as the problems are nasty and difficult to reproduce. I'm not concerned about 2PC or anything of that sort. If we have a commit/rollback problem once in a blue moon, I'm not going to lose any sleep over it. What I've done in an existing Java/Spring project is to write a class that contains a list of Spring's transaction managers and just delegates begin/commit/rollback as appropriate. I'll likely be using plain JDBC or JPA. What would be my options in Lift? Can I get a list of connections and just use a filter (or equivalent) to begin/commit/rollback on each within every request? I've done some searching, but I've not found anything relating to the use of multiple databases. Any advice/pointers would be very much appreciated. Matt -- You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to lift...@googlegroups.com. To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/liftweb?hl=en.
