Re: How to return a large String with C - Mailing list pgsql-general

From Stefan Niantschur
Subject Re: How to return a large String with C
Date
Msg-id 20080217181329.6b0fa26d@trabant.niantschur.de
Whole thread Raw
In response to Re: How to return a large String with C  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: How to return a large String with C
Re: How to return a large String with C
List pgsql-general
Am Sun, 17 Feb 2008 09:17:08 -0500
schrieb Tom Lane <tgl@sss.pgh.pa.us>:

> Stefan Niantschur <sniantschur@web.de> writes:
> > So far I have been successfully doing calls to SPI, select the data
> > from the table and return it. However, this works only with string
> > not larger than page size of char[8192].
> > The strings I expect are much longer and this causes the backend to
> > crash.
>
> Hardly surprising when you're printing the string into a fixed-size
> 8K buffer. The buffer overflow is smashing the stack, in particular
> the function's return address.
>
>             regards, tom lane

Yes, I know, but the backend does not allow for a bigger buffer. Trying
to use a 80K (char[81920])buffer did not work and returns:
INFO:  string-size : 48015
INFO:  +++++++++++++++++++++++++++
server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.
The connection to the server was lost. Attempting reset: Succeeded.


The surprising thing is that the data can be displayed using elog but
not returend with a string pointer.

Is there any good example which I could read?

Best Regards,
Stefan

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