From: | Hannu Krosing <hannu(at)tm(dot)ee> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | Mark kirkwood <markir(at)slingshot(dot)co(dot)nz>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Unbounded (Possibly) Database Size Increase - Toasting |
Date: | 2002-05-20 15:39:28 |
Message-ID: | 1021909168.14280.285.camel@taru.tm.ee |
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Lists: | pgsql-hackers |
On Mon, 2002-05-20 at 16:08, Tom Lane wrote:
> Hannu Krosing <hannu(at)tm(dot)ee> writes:
> > On Sun, 2002-05-19 at 19:37, Tom Lane wrote:
> >> I'd rather expect the toast indexes to grow given the lack-of-btree-
> >> collapse-logic issue.
>
> > Why sould the toast indexes grow significantly more than the primary key
> > of main table ?
>
> Well, the toast indexes will grow because they're using an OID key,
> and so the range of indexed values keeps increasing. AFAIR Mark didn't
> say whether he *had* a primary key, let alone what it was --- but it's
> possible that he has one that has a range that's not changing over the
> test.
his table is this:
CREATE TABLE grow (id integer,body text,CONSTRAINT grow_pk PRIMARY KEY (id))
> In particular, if the test consists simply of updating the toasted
> field, that will not change the primary keys at all ... but it will
> change the toast table's key range, because each new value will get
> a new toast OID.
But does PG not have a new index entry for each _version_ of table row ?
Or does lack-of-btree-collapse-logic affect only keys where there are
many _different_ keys and not many repeating keys?
--------------
Hannu
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