Hi PgQ might be the answer for you. Each transaction shouöd push event into queue and then you can write conusmers that notify each of the applications that need to react to this.
Extract from documentation: PgQ is Postgres based event processing system. It is part of SkyTools package that contains several useful implementations on this engine. SkyTools is scripting framework for Postgres databases written in Python that provides several utilities and implements common database handling logic. Event - atomic piece of data created by Producers. In PgQ event is one record in one of tables that services that queue. Event record contains some system fields for PgQ and several data fileds filled by Producers. PgQ is neither checking nor enforcing event type. Event type is someting that consumer and produser must agree on. PgQ guarantees that each event is seen at least once but it is up to consumer to make sure that event is processed no more than once if that is needed. Batch - PgQ is designed for efficiency and high throughput so events are grouped into batches for bulk processing. Creating these batches is one of main tasks of PgQadm and there are several parameters for each queue that can be use to tune size and frequency of batches. Consumerss receive events in these batches and depending on business requirements process events separately or also in batches. Queue - Event are stored in queue tables i.e queues. Several producers can write into same queeu and several consumers can read from the queue. Events are kept in queue until all the consumers have seen them. We use table rotation to decrease hard disk io. Queue can contain any number of event types it is up to Producer and Consumer to agree on what types of events are passed and how they are encoded For example Londiste producer side can produce events for more tables tan consumer side needs so consumer subscribes only to those tables it needs and events for other tables are ignores. Producer - applicatione that pushes event into queue. Prodecer can be written in any langaage that is able to run stored procedures in Postgres. Consumer - application that reads events from queue. Consumers can be written in any language that can interact with Postgres. SkyTools package contains several useful consumers written in Python that can be used as they are or as good starting points to write more complex consumers. regards, Asko On 9/12/07, Jay Dickon Glanville <[EMAIL PROTECTED]> wrote: > > Hello all. > > Is it possible for PostgreSQL to notify me of a successful transaction > commit? > > Here's an example of what I'm thinking of: > - I write a function (it doesn't matter what language it's in: > PL/pgSQL, PL/Java, etc) > - I register that function as a "post-commit" callback function > - when a client commits a transaction, the function gets called, and > the database passes the function some general information as to the > content of the transaction > > Note how similar this process is to writing triggers. The only > problem I have with triggers is that events get generated per-table. > I'd like to get notifications based on transactions, not table > changes. > > What I'd like to be able to do with this event is to notify any > applications of this change, so they can update their cached view of > the database. > > So, is this possible? Or am I wishing for the sky? ;-) > > Thanks for any help you can provide. > > JDG > > -- > Jay Dickon Glanville > > ---------------------------(end of broadcast)--------------------------- > TIP 9: In versions below 8.0, the planner will ignore your desire to > choose an index scan if your joining column's datatypes do not > match >
