Thanks for the answer What exactly is involved in a checkDs1() call?
Regards LF On Thu, Oct 16, 2014 at 3:33 PM, Romain Manni-Bucau < [email protected]> wrote: > 2014-10-16 15:01 GMT+02:00 Lars-Fredrik Smedberg <[email protected]>: > > Thanks again, see below. > > > > On Thu, Oct 16, 2014 at 2:05 PM, Romain Manni-Bucau < > > [email protected]> wrote: > > > >> 2014-10-16 13:20 GMT+02:00 Lars-Fredrik Smedberg <[email protected]>: > >> > Just one more thing I forgot to put in the other mail > >> > > >> > With "Depend, using ManagedConnection it will be green but it will not > >> do what > >> > you expect." you mean that I will think it runs in a tx but its not > and > >> in > >> > case of failure I might get inconsistency? > >> > > >> > >> right, if datasource2.commit() fails but ds1.commit() passed then you > >> are not consistent. Of course with jpa it is not that impacting since > >> > > > > Could you please explain how jpa tries to solve this? I guess it will not > > completely remove the consisitency risk but only lower the risk? > > > > It doesn't but it limits it in practise. It basically do a check > before calling commit. All checks pass before commit: > > checkDs1(); > checkDs2(); > commitDs1(); > commitDs2(); > > so it avoids half of the ds2 commit fails but not ds1. > > > > >> the provider checks it before committing. > >> > >> > > So I guess in our case: non xa datasources with multiple connections > within > > a transaction we are not guaranteed consistency? > > > > Yep > > > I see also that some db vendors (MQ SQL) has some optimization so > > transactions involving multiple connections from different datasources > but > > from the same db is not promoted to a distributed tx > > > > => Is that only vendor specific or is that according to spec to not > promote > > it in certain situations? > > > > vendor > > > > > resource = datasource != underlying db (without using openejb > >> aliases). Each datasource has its own pool of connection and then its > >> own JTA integration (different Xid). > >> > >> > Regards > >> > LF > >> > > >> > On Thu, Oct 16, 2014 at 12:59 PM, Romain Manni-Bucau < > >> > [email protected]> wrote: > >> > > >> >> Well I don't know websphere enough to answer to the related question > >> >> > >> >> > >> >> 2014-10-16 12:55 GMT+02:00 Lars-Fredrik Smedberg <[email protected] > >: > >> >> > Thanks Romain, please see if you can help me on the follow up > below? > >> >> > > >> >> > > >> >> > On Thu, Oct 16, 2014 at 9:33 AM, Romain Manni-Bucau < > >> >> [email protected]> > >> >> > wrote: > >> >> > > >> >> >> 2014-10-16 9:31 GMT+02:00 Lars-Fredrik Smedberg < > [email protected] > >> >: > >> >> >> > @Romain > >> >> >> > > >> >> >> > I can see in the ManagedConnection code that the reused > Connection > >> is > >> >> per > >> >> >> > Transaction per DataSource. > >> >> >> > > >> >> >> > So if I use 2 x DataSource (pointing to the same DB but with > >> different > >> >> >> > properties set) I will within a transaction use 2 connections, > >> >> correct? > >> >> >> > > >> >> >> yep > >> >> >> > >> >> >> > Will this result in a distributed transaction? > >> >> >> > > >> >> >> > >> >> >> No, this ManagedConnection is to get JTA integration "locally" > (ie we > >> >> >> integrate locally with XA hooks but it is not distributed). For > that > >> >> >> you have to use a really XA datasource. > >> >> >> > >> >> > > >> >> > We use WebSphere in test/production and the driver included in > >> >> db2jcc4.jar. > >> >> > > >> >> > As far as I understand from the documentation if the type > attribute of > >> >> the > >> >> > datasource element in the configuration is not set it will search > the > >> >> > driver jar for datasources in the following order: > >> >> > > >> >> > javax.sql.ConnectionPoolDataSource > >> >> > javax.sql.DataSource > >> >> > javax.sql.XADataSource > >> >> > > >> >> > In our testconfiguration we do not specify the type attribute so I > >> assume > >> >> > we are NOT using XA datasource. correct? > >> >> > > >> >> > So some questions on the above: > >> >> > > >> >> > 1. In what cases will I not need a distributed tx? > >> >> > >> >> You don't need it either when you have a single or totally > decorelated > >> >> resources (datasource for instane) or when you want performances (XA > >> >> is slow) and can accept some manual operations to fix inconsistency > if > >> >> it happens (should be rare) > >> >> > >> >> > a) A tx with 1 connection to a DB? No! > >> >> > b) A tx with 2 connections (from seperate datasources) connected to > >> the > >> >> > same DB? <== ?? > >> >> > c) A tx with 2 connections (from seperate datasources) connected to > >> >> > different DBs? Yes! > >> >> > d) A tx with 1 connection to a DB and e.g. JMS? Yes! > >> >> > > >> >> > 2. If I have a scenario that requires a distributed and the > datasource > >> >> that > >> >> > is used is NOT an XA datasource what will happen? Exception? > >> >> > > >> >> > >> >> Depend, using ManagedConnection it will be green but it will not do > >> >> what you expect. > >> >> > >> >> > Thanks > >> >> > > >> >> > Regards > >> >> > Lars-Fredrik > >> >> > > >> >> > > >> >> > > >> >> >> > >> >> >> > Regards > >> >> >> > LF > >> >> >> > > >> >> >> > On Wed, Oct 15, 2014 at 8:48 AM, Romain Manni-Bucau < > >> >> >> [email protected]> > >> >> >> > wrote: > >> >> >> > > >> >> >> >> Hi > >> >> >> >> > >> >> >> >> that's the global idea yes > >> >> >> >> > >> >> >> >> about transaction manager: > >> >> >> >> > >> >> >> >> > >> >> >> > >> >> > >> > http://grepcode.com/file/repo1.maven.org/maven2/org.apache.geronimo.components/geronimo-transaction/3.1.1/org/apache/geronimo/transaction/manager/TransactionManagerImpl.java#TransactionManagerImpl > >> >> >> >> is th eone > >> >> >> >> > >> >> >> >> idea is simple: invoke registered hooks when needed and just > >> manage > >> >> >> >> the lifecycle then EJB containers start/stop these hooks > calling > >> the > >> >> >> >> tx mgr (look SingletonContainer hierarchy in openejb-core for > >> >> >> >> instance) > >> >> >> >> > >> >> >> >> > >> >> >> >> Romain Manni-Bucau > >> >> >> >> @rmannibucau > >> >> >> >> http://www.tomitribe.com > >> >> >> >> http://rmannibucau.wordpress.com > >> >> >> >> https://github.com/rmannibucau > >> >> >> >> > >> >> >> >> > >> >> >> >> 2014-10-15 1:19 GMT+02:00 Lars-Fredrik Smedberg < > >> [email protected] > >> >> >: > >> >> >> >> > Hi Romain > >> >> >> >> > > >> >> >> >> > Thanks for the link to the ManagedConnection, some questions > on > >> it > >> >> >> (so I > >> >> >> >> > understand it correctly) > >> >> >> >> > > >> >> >> >> > - The connection is bound to the tx when the first method is > >> >> called on > >> >> >> >> the > >> >> >> >> > connect (except for toString, equals and hashcode), and if > its > >> not > >> >> >> >> already > >> >> >> >> > bound, correct? > >> >> >> >> > - Do I understand correctly that I will always use (using > >> >> delegation > >> >> >> in > >> >> >> >> the > >> >> >> >> > proxy) the same connection (the one bound to the tx) > regardless > >> of > >> >> if > >> >> >> I > >> >> >> >> use > >> >> >> >> > getConnection()/close() multiple times within an EJB that > >> handles > >> >> tx? > >> >> >> >> > - In the above case the connection I think I'm using (when I > >> simple > >> >> >> look > >> >> >> >> at > >> >> >> >> > the code) is returned to the pool and the bound one is used? > >> >> >> >> > > >> >> >> >> > Where can I get more understanding of the TransactionManager > and > >> >> its > >> >> >> >> > relation to the transactions annotated in the EJB? > >> >> >> >> > > >> >> >> >> > Very nice to take a look at the code, really makes the > >> >> understanding > >> >> >> alot > >> >> >> >> > easier, thanks! > >> >> >> >> > > >> >> >> >> > /LF > >> >> >> >> > > >> >> >> >> > > >> >> >> >> > On Wed, Oct 15, 2014 at 1:03 AM, Romain Manni-Bucau < > >> >> >> >> [email protected]> > >> >> >> >> > wrote: > >> >> >> >> > > >> >> >> >> >> Hi > >> >> >> >> >> > >> >> >> >> >> this is actually more bound to JTA (you can read > >> >> >> >> >> > >> >> >> >> >> > >> >> >> >> > >> >> >> > >> >> > >> > http://svn.apache.org/repos/asf/tomee/tomee/trunk/container/openejb-core/src/main/java/org/apache/openejb/resource/jdbc/managed/local/ManagedConnection.java > >> >> >> >> >> ) > >> >> >> >> >> > >> >> >> >> >> > >> >> >> >> >> 2014-10-15 0:14 GMT+02:00 Lars-Fredrik Smedberg < > >> >> [email protected] > >> >> >> >: > >> >> >> >> >> > Hi > >> >> >> >> >> > > >> >> >> >> >> > Using JDBC, creating a connection and setting it to auto > >> commit > >> >> >> false > >> >> >> >> to > >> >> >> >> >> be > >> >> >> >> >> > able to group more than one statement into a single > >> transaction > >> >> I > >> >> >> >> >> > understand. > >> >> >> >> >> > > >> >> >> >> >> > - Is it possible to compare that to an EJB with a > >> >> >> >> @TransactionAttribute > >> >> >> >> >> > set? I would like to understand more in detail how the EJB > >> >> handles > >> >> >> >> >> > transactions, datasources and connections "under the > hood". > >> >> >> >> >> > (it all comes from a discussion with a DBA) > >> >> >> >> >> > > >> >> >> >> >> > If I use @Resource to inject a Datasource and use to > >> retrieve a > >> >> >> >> >> connection > >> >> >> >> >> > I usually call close on it after I done using it, > >> >> >> >> >> > > >> >> >> >> >> > - Will close on the connection actually close it or is > that > >> >> done at > >> >> >> >> the > >> >> >> >> >> > commit of the transaction (assume we are in an EJB with > >> >> >> >> >> > @TransactionAttribute set)? > >> >> >> >> >> > >> >> >> >> >> will be done later to support rollback > >> >> >> >> >> > >> >> >> >> >> > - Will the container automatically set auto commit false > to > >> any > >> >> >> >> >> connections > >> >> >> >> >> > retrieved within the transaction? > >> >> >> >> >> > >> >> >> >> >> all JTA ones, can also depend on JPA provider config > >> >> >> >> >> > >> >> >> >> >> > - ... and many more questions :) > >> >> >> >> >> > > >> >> >> >> >> > Maybe I'm mixing the topics a bit but it would be really > >> great > >> >> to > >> >> >> >> >> > understand it all more in-depth to be able to have the > >> >> >> understanding > >> >> >> >> and > >> >> >> >> >> > discuss it with the DBA. > >> >> >> >> >> > > >> >> >> >> >> > Thanks > >> >> >> >> >> > > >> >> >> >> >> > > >> >> >> >> >> > > >> >> >> >> >> > -- > >> >> >> >> >> > Med vänlig hälsning / Best regards > >> >> >> >> >> > > >> >> >> >> >> > Lars-Fredrik Smedberg > >> >> >> >> >> > > >> >> >> >> >> > STATEMENT OF CONFIDENTIALITY: > >> >> >> >> >> > The information contained in this electronic message and > any > >> >> >> >> >> > attachments to this message are intended for the exclusive > >> use > >> >> of > >> >> >> the > >> >> >> >> >> > address(es) and may contain confidential or privileged > >> >> >> information. If > >> >> >> >> >> > you are not the intended recipient, please notify > >> Lars-Fredrik > >> >> >> >> Smedberg > >> >> >> >> >> > immediately at [email protected], and destroy all > copies of > >> >> this > >> >> >> >> >> > message and any attachments. > >> >> >> >> >> > >> >> >> >> > > >> >> >> >> > > >> >> >> >> > > >> >> >> >> > -- > >> >> >> >> > Med vänlig hälsning / Best regards > >> >> >> >> > > >> >> >> >> > Lars-Fredrik Smedberg > >> >> >> >> > > >> >> >> >> > STATEMENT OF CONFIDENTIALITY: > >> >> >> >> > The information contained in this electronic message and any > >> >> >> >> > attachments to this message are intended for the exclusive > use > >> of > >> >> the > >> >> >> >> > address(es) and may contain confidential or privileged > >> >> information. If > >> >> >> >> > you are not the intended recipient, please notify > Lars-Fredrik > >> >> >> Smedberg > >> >> >> >> > immediately at [email protected], and destroy all copies of > >> this > >> >> >> >> > message and any attachments. > >> >> >> >> > >> >> >> > > >> >> >> > > >> >> >> > > >> >> >> > -- > >> >> >> > Med vänlig hälsning / Best regards > >> >> >> > > >> >> >> > Lars-Fredrik Smedberg > >> >> >> > > >> >> >> > STATEMENT OF CONFIDENTIALITY: > >> >> >> > The information contained in this electronic message and any > >> >> >> > attachments to this message are intended for the exclusive use > of > >> the > >> >> >> > address(es) and may contain confidential or privileged > >> information. If > >> >> >> > you are not the intended recipient, please notify Lars-Fredrik > >> >> Smedberg > >> >> >> > immediately at [email protected], and destroy all copies of > this > >> >> >> > message and any attachments. > >> >> >> > >> >> > > >> >> > > >> >> > > >> >> > -- > >> >> > Med vänlig hälsning / Best regards > >> >> > > >> >> > Lars-Fredrik Smedberg > >> >> > > >> >> > STATEMENT OF CONFIDENTIALITY: > >> >> > The information contained in this electronic message and any > >> >> > attachments to this message are intended for the exclusive use of > the > >> >> > address(es) and may contain confidential or privileged > information. If > >> >> > you are not the intended recipient, please notify Lars-Fredrik > >> Smedberg > >> >> > immediately at [email protected], and destroy all copies of this > >> >> > message and any attachments. > >> >> > >> > > >> > > >> > > >> > -- > >> > Med vänlig hälsning / Best regards > >> > > >> > Lars-Fredrik Smedberg > >> > > >> > STATEMENT OF CONFIDENTIALITY: > >> > The information contained in this electronic message and any > >> > attachments to this message are intended for the exclusive use of the > >> > address(es) and may contain confidential or privileged information. If > >> > you are not the intended recipient, please notify Lars-Fredrik > Smedberg > >> > immediately at [email protected], and destroy all copies of this > >> > message and any attachments. > >> > > > > > > > > -- > > Med vänlig hälsning / Best regards > > > > Lars-Fredrik Smedberg > > > > STATEMENT OF CONFIDENTIALITY: > > The information contained in this electronic message and any > > attachments to this message are intended for the exclusive use of the > > address(es) and may contain confidential or privileged information. If > > you are not the intended recipient, please notify Lars-Fredrik Smedberg > > immediately at [email protected], and destroy all copies of this > > message and any attachments. > -- Med vänlig hälsning / Best regards Lars-Fredrik Smedberg STATEMENT OF CONFIDENTIALITY: The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the address(es) and may contain confidential or privileged information. If you are not the intended recipient, please notify Lars-Fredrik Smedberg immediately at [email protected], and destroy all copies of this message and any attachments.
