Re: [GENERAL] [HACKERS] Threads in PostgreSQL

[Atri Sharma]

On Mon, Dec 21, 2015 at 11:51 AM, 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.*
>
>

PostgreSQL is a process-per-backend model.

Can you elaborate on what you are using the threads for?

Re: [GENERAL] [HACKERS] Threads in PostgreSQL

[Konstantin Knizhnik]

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