Re: Unbounded (Possibly) Database Size Increase - Toasting

From: <markir(at)slingshot(dot)co(dot)nz>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Hannu Krosing <hannu(at)tm(dot)ee>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Unbounded (Possibly) Database Size Increase - Toasting
Date: 2002-05-20 21:37:17
Message-ID: 20020520213912.2DB2D475D3C@postgresql.org
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>
> Hmm. Which file(s) were growing, exactly? How many row updates is this
> run covering?
>

The toast table gets about 90 percent of the growth, followed by the toast
index at about 9 percent. The actual table + primary key stay at about 2M each.

I neglected to mention what the update statement actually was :

UPDATE grow SET body = ? WHERE id = ?

So the untoasted elements are not being altered at all...

A typical run has 2 threads each of which updates the entire table (20,000
rows) every 2000 s.

The vacuum thread manages to get 6-7 vacuums in before both threads update the
entire table.

regards

Mark

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