Re: DRDA, network protocol, and documentation
От | Brian Bruns |
---|---|
Тема | Re: DRDA, network protocol, and documentation |
Дата | |
Msg-id | Pine.LNX.4.33.0202071601590.14563-100000@localhost.localdomain обсуждение исходный текст |
Ответ на | Re: DRDA, network protocol, and documentation (Hannu Krosing <hannu@tm.ee>) |
Список | pgsql-hackers |
On 7 Feb 2002, Hannu Krosing wrote: > But I guess that you can't fake PREPARE/EXECUTE on client side anymore > if you want to be DRDA compatible? DRDA has a facility for preparing and executing, but also for direct execution. So, a server implementation would have to support all of the AR Level 1 capabilities to be compatible. The client is a bit free-er to choose how to send it's SQL. That is, the client has the option to fake a prepare/execute but the server must service either method. > Does DRDA have standard representation of datatypes on wire ? DRDA has a quite extensive list of datatype representations. The ordering of bytes is server dictated (as opposed to TDS where it is client dictated, so server does the byte swapping if necessary). > If so, how will postgres extendable datatypes fit in there ? > > I know that postgres's system tables have two sets of type i/o functions > typinput | regproc | > typoutput | regproc | > typreceive | regproc | > typsend | regproc | > > which are currently initialised to the same real functions > > hannu=# select count(*) from pg_type where typoutput <> typsend or > typinput <> typreceive; > count > ------- > 0 > (1 row) The server has the leeway to determine the DRDA representation for it's dataytpes, and it is the clients responsibility to deal with it. > I suspect thet the typreceive and typsend were planned for some common > network representation, but such usage has probaly gone untested for a > very long time. good question. Brian
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