No, it can be anything else. Please correctly me if I'm wrong, but to me, PgPool-II looks like a proxy server that forwards all the data without interpretation. Can I intercept in the middle and control the flow between client and server? For e.g, I need control when the result of transaction is sent back to the result?
On Sat, Aug 20, 2016 at 2:39 AM, Craig Ringer <cr...@2ndquadrant.com> wrote: > On 19 August 2016 at 22:16, Joshua Bay <joshuaba...@gmail.com> wrote: > >> Oh I see. >> I just read more on use cases PgBouncer, but seems like it can't be used >> for my project. >> The reason is that I need to have my middleware to have full control over >> each transaction. >> That is it must be able to decide if it's going to commit or abort a >> single query (reason why libpq is used in the middleware), and it must be >> able to decide when to send back the result. Also it does things like load >> balancing with it's algorithm. >> >> So, what middleware does is (simplied, ignoring other details) >> 1. listens to query and does load balancing >> 2. execute query on behalf of client to server with libpq (does not have >> to be libpq). >> 3. serialize the result and send it back >> >> And the #3 is why I asked for ways to serialize PGresult (of libpq) >> >> Client app will deserialize the result and thus be able to interpret >> PGresult as if it used libpq itself. >> >> > Surely the app should just use libpq, and your middleware should be a > proxy? > > Like, say, PgPool-II? > > Otherwise you'll have to extract all the results handling parts of libpq > into some smaller cut-down library and graft on > serialization/deserialization code. There's nothing built-in for that > ,since the natural and logical serialization for query results is the > PostgreSQL wire protocol. > > -- > Craig Ringer http://www.2ndQuadrant.com/ > PostgreSQL Development, 24x7 Support, Training & Services >
