Re: [HACKERS] Threads in PostgreSQL

Konstantin Knizhnik <k.knizhnik@xxxxxxxxxxxxxx> · Mon, 21 Dec 2015 10:48:52 +0300



    Hi, 

    
    PostgreSQL is not using threads but it is possible to spawn thread
    in your PostgreSQL extensions.

    For example, I have used pool of threads in my IMCS extension.

    But you need to build your  extension with -pthread:

    
    CUSTOM_COPT = -pthread

    
    Also, please take in account that many PostgreSQL functions (even
    in/out or comparison functions) are not reentrant: them are storing
    their state in global variables.

    So you will get race conditions if you are calling  such functions
    from multiple threads.

    
    Concerning stack overflow, I think that the most probable reason is
    trivial infinite recursion. 

    Did you inspect stack trace in debugger?

    
    On 21.12.2015 09:21, sri harsha wrote:

    
      Hi,
        

           Is it possible to use threads in Postgresql ?? I am
          using threads in my foreign data wrapper and i get the
          following error when i use the threads .
        

          ERROR:  stack depth limit exceeded
          HINT:  Increase the configuration
                parameter "max_stack_depth" (currently 2048kB), after
                ensuring the platform's stack depth limit is adequate.
        
        
        No matter how much i increase the stack size , the error
          keeps occurring . How do i solve this problem ??
        

        Thanks,
        Harsha