Re: vacuum full 100 mins plus?

Tom Lane wrote:

> Christopher Browne <cbbrowne(at)acm(dot)org> writes:
>> A long time ago, in a galaxy far, farpliers PHatcher(at)macys(dot)com (Patrick
>> Hatcher) wrote:
>>> Answered my own question. I gave up the vacuum full after 150 mins. I
>>> was able to export to a file, vacuum full the empty table, and reimport
>>> in less
>>> than 10 mins. I suspect the empty item pointers and the sheer number of
>>> removable rows was causing an issue.
>
>> In that case, you'd be a little further better off if the steps were:
>> - drop indices;
>> - copy table to file (perhaps via pg_dump -t my_table);
>> - truncate the table, or drop-and-recreate, both of which make
>> it unnecessary to do _any_ vacuum of the result;
>> - recreate indices, probably with SORT_MEM set high, to minimize
>> paging to disk
>> - analyze the table (no need to vacuum if you haven't created any
>> dead tuples)
>> - cut SORT_MEM back down to "normal" sizes
>
> Rather than doing all this manually, you can just CLUSTER on any handy
> index. In 7.5, another possibility is to issue one of the forms of
> ALTER TABLE that force a table rewrite.
>
> The range of usefulness of VACUUM FULL is really looking narrower and
> narrower to me. I can foresee a day when we'll abandon it completely.

I would love to see this 10lb sledge hammer go away when we have enough tiny
screwdrivers and needlenose pliers to make it obsolete!

>
> regards, tom lane
>
> ---------------------------(end of broadcast)---------------------------
> TIP 5: Have you checked our extensive FAQ?
>
> http://www.postgresql.org/docs/faqs/FAQ.html