Re: scrollable cursor sup. for SPI

From: "Pavel Stehule" <pavel(dot)stehule(at)hotmail(dot)com>
To: tgl(at)sss(dot)pgh(dot)pa(dot)us, neilc(at)samurai(dot)com
Cc: pgsql-patches(at)postgresql(dot)org, jonah(dot)harris(at)gmail(dot)com
Subject: Re: scrollable cursor sup. for SPI
Date: 2007-01-16 04:33:45
Message-ID: BAY20-F805F83DC8E870FED70C23F9B40@phx.gbl
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-patches

>Neil Conway <neilc(at)samurai(dot)com> writes:
> > BTW, how do people feel about the function names:
>
> > SPI_cursor_open_with_options
> > SPI_scroll_cursor_fetch
> > SPI_scroll_cursor_move
>
>I dislike the SPI_cursor_open_with_options API on the grounds that it
>lets people break things (CURSOR_OPT_HOLD for instance isn't likely
>to do anything good) and it doesn't actually provide any functionality
>that wasn't there before (the existing code already sets OPT_SCROLL
>if possible). I'd suggest losing that one entirely and just adding
>the FetchDirection-as-substitute-for-"forward" entry points.
>

First variant of this "open" function controlls only sroll option. But there
are other option which we have to controll in futere like INSENSITIVE,
SENSITIVE, FOR UPDATE and it's reason for _with_options.

if I comprehended it well CURSOR_OPT_SCROLL is set only when SCROLL is cheap
(not when is possible). It's true?

/*
* Set up options for portal.
*
* If the user didn't specify a SCROLL type, allow or disallow
scrolling
* based on whether it would require any additional runtime overhead
to do
* so.
*/
portal->cursorOptions = stmt->options;
if (!(portal->cursorOptions & (CURSOR_OPT_SCROLL |
CURSOR_OPT_NO_SCROLL)))
{
if (ExecSupportsBackwardScan(plan))
portal->cursorOptions |= CURSOR_OPT_SCROLL;
else
portal->cursorOptions |= CURSOR_OPT_NO_SCROLL;

_________________________________________________________________
Najdete si svou lasku a nove pratele na Match.com. http://www.msn.cz/

In response to

Responses

Browse pgsql-patches by date

  From Date Subject
Next Message Tom Lane 2007-01-16 04:45:18 Re: scrollable cursor sup. for SPI
Previous Message CN 2007-01-16 03:09:36 Re: BCC55 and libpq 8.2