Re: TOAST-slicing: substring access methods for TOASTed values.

Your patch has been added to the PostgreSQL unapplied patches list at:

    http://candle.pha.pa.us/cgi-bin/pgpatches

I will try to apply it within the next 48 hours.

---------------------------------------------------------------------------


John Gray wrote:
> Hi all,
>
> I attach a version of my toast-slicing patch, against current CVS
> (current as of a few hours ago.)
>
> This patch:
>
> 1. Adds PG_GETARG_xxx_P_SLICE() macros and associated support routines.
>
> 2. Adds routines in src/backend/access/tuptoaster.c for fetching only
> necessary chunks of a toasted value. (Modelled on latest changes to
> assume chunks are returned in order).
>
> 3. Amends text_substr and bytea_substr to use new methods. It now
> handles multibyte cases -and should still lead to a performance
> improvement in the multibyte case where the substring is near the
> beginning of the string.
>
> 4. Added new command: ALTER TABLE tabname ALTER COLUMN colname SET
> STORAGE {PLAIN | EXTERNAL | EXTENDED | MAIN} to parser and documented in
> alter-table.sgml. (NB I used ColId as the item type for the storage
> mode string, rather than a new production - I hope this makes sense!).
> All this does is sets attstorage for the specified column.
>
> 4. AlterTableAlterColumnStatistics is now AlterTableAlterColumnFlags and
> handles both statistics and storage (it uses the subtype code to
> distinguish). The previous version of my patch also re-arranged other
> code in backend/commands/command.c but I have dropped that from this
> patch.(I plan to return to it separately).
>
> 5. Documented new macros (and also the PG_GETARG_xxx_P_COPY macros) in
> xfunc.sgml. ref/alter_table.sgml also contains documentation for ALTER
> COLUMN SET STORAGE.
>
> Comments or suggestions welcome.
>
> John
>
>
>
>
>

[ Attachment, skipping... ]

>
> ---------------------------(end of broadcast)---------------------------
> TIP 6: Have you searched our list archives?
>
> http://archives.postgresql.org

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026