Re: Postgres INSERT performance and scalability - Mailing list pgsql-performance

* Jon Nelson (jnelson+pgsql@jamponi.net) wrote:
> Isn't the WAL basically COW?

eh..?  No..  The WAL is used to record what changes are made to the
various files in the database, it certainly isn't an kind of
"copy-on-write" system, where we wait until a change is made to data
before copying it..

If you INSERT .. SELECT, you're going to get the real data in the WAL,
and also in the heap of the new table..

    Thanks,

        Stephen