Re: insert vs select into performance

Have you also tried the COPY-statement? Afaik select into is similar to
what happens in there.

Best regards,

Arjen

On 17-7-2007 21:38 Thomas Finneid wrote:
> Hi
>
> I was doing some testing on "insert" compared to "select into". I
> inserted 100 000 rows (with 8 column values) into a table, which took 14
> seconds, compared to a select into, which took 0.8 seconds.
> (fyi, the inserts where batched, autocommit was turned off and it all
> happend on the local machine)
>
> Now I am wondering why the select into is that much faster?
> Does the select into translate into a specially optimised function in c
> that can cut corners which a insert can not do (e.g. lazy copying), or
> is it some other reason?
>
> The reason I am asking is that select into shows that a number of rows
> can be inserted into a table quite a lot faster than one would think was
> possible with ordinary sql. If that is the case, it means that if I
> write an pl-pgsql insert function in C instead of sql, then I can have
> my db perform order of magnitude faster.
>
> Any comments?
>
> regards
>
> thomas
>
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