Re: Cancelling Requests Frontend/Backend Protocol TCP/IP - Mailing list pgsql-general

From Tom Lane
Subject Re: Cancelling Requests Frontend/Backend Protocol TCP/IP
Date
Msg-id 4881.1257179732@sss.pgh.pa.us
Whole thread Raw
In response to Re: Cancelling Requests Frontend/Backend Protocol TCP/IP  (Raimon Fernandez <coder@montx.com>)
Responses Re: Cancelling Requests Frontend/Backend Protocol TCP/IP
List pgsql-general
Raimon Fernandez <coder@montx.com> writes:
> Quoted from the documentation:
> "The cancellation signal might or might not have any effect — for
> example, if it arrives after the
> backend has finished processing the query, then it will have no
> effect.

> Here I understand that maybe it will have NO effect, so postgresql
> will still sending rows and rows and rows ...

If you're too late, the backend has already sent all the rows.  There's
not much we can do about data that's already in flight.  There probably
won't be that much of it though, as TCP stacks don't buffer infinite
amounts of data.

            regards, tom lane

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