Hi Sven and thanks for answering! I use Teapot with one common sql-connecton, not one for each user session. At startup I create several sql statements and these does not seem to be usable from different Teapot request at the same time.
I could create one connection pr. session and then close the database connection when the user leaves, but then I also would need to create all the prepared sql-statements for each session, which does not sound right to me? It seems I have will have to look into the other solution, and see if I can use some mutex stuff to avoid several tasks acessessing the same resources at the same time,. Creating a pool sounds like the right solution to me now - any meaning about this? Petter On Sun, Feb 9, 2020 at 4:52 PM Sven Van Caekenberghe <[email protected]> wrote: > Hi Petter, > > [ CC-ing the Pharo Users list ] > > P3Client is not built/designed to be used by multiple processes > concurrently. Each database connection is represented by an instance of > P3Client and holds some state both at the client as well as at the server > side. > > Typically, in a multi user server application, each connection should have > its own P3Client / psql connection. For example, in Seaside, a custom > WASession subclass gives each session/user its own p3 connection/client. > > Is that what you are doing ? > > If not, you could wrap your db accessing code so that mutual exclusion is > provided. For example, you can have a look at AbstractCache #beThreadSafe > and #critical: > > That will then serialise requests and possibly block one onto the other. > > HTH, > > Sven > > PS: another thing to take care of if closing your sql connections when the > session is no longer needed. > > PS: Zinc HTTP does also provide a session mechanism > (ZnServerSession[Manager]) but these work with cookies and typically won't > help with a REST access pattern. > > > On 9 Feb 2020, at 14:21, Petter Egesund <[email protected]> > wrote: > > > > Hi Sven > > > > We are using Pharo as our backend in a project and we have run into a > problem with P3. > > > > The problem seems to be connected to compiled sql statements and > concurrency. > > > > We keep getting this error: Bindcomplete message expected > > > > Problem seems to be easy to reproduce: > > > > 1) Compile any sql statement > > 2) Use this statement in a query twice (!) in a teapot endpoint > > > > The run some concurrent queries, like "curl > http://localhost:8080/endpoint & curl http://localhost:8080/endpoint.."; > (add several curls after here). > > > > One could also use ex. siege ( > https://manpages.ubuntu.com/manpages/trusty/man1/siege.1.html) for easy > reproducing. > > > > If we chain the curls after each other, like "curl > http://localhost:8080/endpoint && > https://manpages.ubuntu.com/manpages/trusty/man1/siege.1.html && > https://manpages.ubuntu.com/manpages/trusty/man1/siege.1.html.."; it seems > to work fine, so doing the request sequentially seem to work fine. > > > > My conclusion is that this must be connected to how teapot handles > concurrency in companion with the compiled statements? > > > > Any clues on this one? We are on Pharo 8.0 with latest version of P3, PG > 9.x) > > > > Best regards > > > > Petter Egesund (I wrote the heysql-package based on P3) > >
