Re: index file bloating still in 7.4 ?

From: Seum-Lim Gan <slgan(at)lucent(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: josh(at)agliodbs(dot)com, pgsql-performance(at)postgresql(dot)org
Subject: Re: index file bloating still in 7.4 ?
Date: 2003-10-19 05:11:13
Message-ID: p0510030ebbb7cabb0ceb@[192.168.10.52]
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Hi Tom,

I did that when I have stopped my updates.

Now, I am doing updates below is the output of vacuum.
After doing the vacuum verbose analyze, it reported the following :

INFO: vacuuming "craft.dsperf_rda_or_key"
INFO: index "hello242_1105" now contains 1792276 row versions in 6237 pages
DETAIL: 0 index pages have been deleted, 0 are currently reusable.
CPU 0.61s/0.36u sec elapsed 17.92 sec.
INFO: "hello_rda_or_key": found 0 removable, 1791736 nonremovable
row versions in 30892 pages
DETAIL: 1492218 dead row versions cannot be removed yet.
There were 0 unused item pointers.
0 pages are entirely empty.
CPU 1.95s/1.99u sec elapsed 26.95 sec.
INFO: analyzing "craft.dsperf_rda_or_key"
INFO: "hello_rda_or_key": 30909 pages, 3000 rows sampled, 93292
estimated total rows
VACUUM

Gan

At 10:21 pm -0400 2003/10/18, Tom Lane wrote:
>Seum-Lim Gan <slgan(at)lucent(dot)com> writes:
>> Sample verbose analyze:
>
>> VACUUM VERBOSE ANALYZE hello_rda_or_key;
>> INFO: vacuuming "craft.hello_rda_or_key"
>> INFO: index "hello242_1105" now contains 740813 row versions in 2477 pages
>
>So what's the problem? That doesn't seem like a particularly bloated
>index. You didn't say what datatype the index is on, but making the
>most optimistic assumptions, index entries must use at least 16 bytes
>each. You're getting about 300 entries per page, compared to the
>theoretical limit of 512 ... actually more, since I'm not allowing for
>upper btree levels in this calculation ... which says to me that the
>page loading is right around the expected btree loading of 2/3.
>
> regards, tom lane

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