sid vs pid
Mary Green asked how sid and pid in sysmaster's syssessions differ. Fernando Nunes said one OS process (PID) can have several database sessions (SID). Art Kagel added that PID is the client process id, unrelated to the server, and one session (SID) can have many thread IDs under parallel query or sorting. Mary understood; she had confused process with thread.
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What is the difference between the sid and the pid (in the syssessions table of the sysmaster database)? I assume that sid stands for session ID and pid for process ID. If that is correct, then a session could have more than one process running at a time. Is that right?
No... An operating system process (PID) can have more than one database session (SID) Regards. On Sat, Jul 8, 2017 at 1:18 AM, MARY GREEN <mgreen@flyravn.com> wrote: > What is the difference between the sid and the pid (in the syssessions > table > of the sysmaster database)? I assume that sid stands for session ID and pid > for process ID. If that is correct, then a session could have more than one > process running at a time. Is that right? > > > ************************************************************ > ******************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > -- Fernando Nunes Portugal http://informix-technology.blogspot.com My email works... but I don't check it frequently...
Thanks. I thought the process ID was for a DBMS process. I probably had process confused with thread.
Unless the session call an SPL/UDR that runs multiple system commands ...... but that is being pedantic Paul Watson Oninit www.oninit.com +1 913 387 7529 Oninit® is a Registered Trademark of Oninit LLC > On Jul 7, 2017, at 19:25, Fernando Nunes <domusonline@gmail.com> wrote: > > No... An operating system process (PID) can have more than one database > session (SID) > Regards. > >> On Sat, Jul 8, 2017 at 1:18 AM, MARY GREEN <mgreen@flyravn.com> wrote: >> >> What is the difference between the sid and the pid (in the syssessions >> table >> of the sysmaster database)? I assume that sid stands for session ID and pid >> for process ID. If that is correct, then a session could have more than one >> process running at a time. Is that right? >> >> >> ************************************************************ >> ******************* >> Forum Note: Use "Reply" to post a response in the discussion forum. >> >> > > -- > Fernando Nunes > Portugal > > http://informix-technology.blogspot.com > My email works... but I don't check it frequently... > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum.
No. PID is the client process id and is not directly related to the server itself. A client session has a single SID or Session ID associated with it but can have many TIDs or Thread IDs if it is multi-threaded inside the engine due to parallel query or parallel sorting. Art Art S. Kagel, President and Principal Consultant ASK Database Management www.askdbmgt.com Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Fri, Jul 7, 2017 at 7:18 PM, MARY GREEN <mgreen@flyravn.com> wrote: > What is the difference between the sid and the pid (in the syssessions > table > of the sysmaster database)? I assume that sid stands for session ID and pid > for process ID. If that is correct, then a session could have more than one > process running at a time. Is that right? > > > ************************************************************ > ******************* > Forum Note: Use "Reply" to post a response in the discussion forum. > >