| From: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
|---|---|
| To: | Jan Wieck <JanWieck(at)Yahoo(dot)com> |
| Cc: | PostgreSQL HACKERS <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: TOAST & vacuum |
| Date: | 2000-07-27 02:10:05 |
| Message-ID: | 200007270210.WAA10521@candle.pha.pa.us |
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| Thread: | |
| Lists: | pgsql-hackers |
> FYI,
>
> TOAST is now vacuum-safe. When needed, the toaster creates a
> second heap tuple, containing only plain or compressed
> values. This one is then returned by the heap access methods
> to the caller, so indices will never contain external
> references.
>
> The changes are covered by #ifdef TOAST_INDICES, so can
> easily be disabled at the time we have file versioning and
> can recreate indices during vacuum.
Seems this has some performance advantages. Un-toasting to traverse a
btree index would be pretty slow. This way, it is all in the index.
--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026
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