Re: Why the size (PQ_BUFFER_SIZE) of backend send buffers is 8192 ?

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Il 03/01/2014 09:47, xbzhang ha scritto:
> Why the size (PQ_BUFFER_SIZE) of backend send buffers is 8192 ?
> Can i set it to other value ?

In principle, it is just an arbitrary amount by which to increase the
I/O buffer size. Of course it has to take into account the buffering
behaviour of the system kernel and TCP stack.

> If i extend or decrease it , can it affect the performance of
> sending message?

PQ_BUFFER_SIZE handle the low-level details of communication between
frontend and backend. I would not decrease its value, there is no
reason to expect advantage splitting 8k buffers (i.e. a page content
size) in my opinion.

Giuseppe.
- --
Giuseppe Broccolo - 2ndQuadrant Italy
PostgreSQL Training, Services and Support
giuseppe(dot)broccolo(at)2ndQuadrant(dot)it | www.2ndQuadrant.it
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