Re: [HACKERS] - WIP Patch Updatable Cursor

From: Gavin Sherry <swm(at)alcove(dot)com(dot)au>
To: John Bartlett <johnb(at)fast(dot)fujitsu(dot)com(dot)au>
Cc: pgsql-hackers(at)postgresql(dot)org, pgsql-patches(at)postgresql(dot)org, "'Heikki Linnakangas'" <heikki(at)enterprisedb(dot)com>
Subject: Re: [HACKERS] - WIP Patch Updatable Cursor
Date: 2007-02-28 04:22:30
Message-ID: Pine.LNX.4.58.0702281518260.8805@linuxworld.com.au
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On Wed, 28 Feb 2007, John Bartlett wrote:

> Hi,
>
> A list of ctids is stored in the file.

I would have thought these would be stored in memory. If the set got
large, you'd use a temporary file the way other systems which overflow to
disk do?

>
> The file is used to store the ctids during an updatable cursor transaction.
>
> It is set up as a permanent file as it has a potential lifetime of
> preserving data between crashes of the backend. Temporary files tend to be
> used for data that is defined within a single command. In this case the file
> needs to exist within a transaction and across backend processes.

It does not. Cursors are implicitly closed when a session is closed. A
backend crash or system restart closes all open sessions.

>
> The file gram.y has been corrected in my version.
>
> The files ctidListStore.c and ctidListStore.h were pasted into the patch
> file, as the diff -N command produced a file of several hundred thousand
> lines.

Edit the file with a text editor. If you know which files should be
excluded (like tags files), use diff --exclude=<pattern>.

Thanks,

Gavin

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