Re: Unbounded (Possibly) Database Size Increase - Toasting

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Hannu Krosing <hannu(at)tm(dot)ee>
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 14:08:16
Message-ID: 22174.1021903696@sss.pgh.pa.us
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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.

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.

regards, tom lane

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