On Tue, Aug 23, 2016 at 6:04 AM, Jerome Wagner <jerome.wag...@laposte.net> wrote:
> Hello, > > in the documentation I read > https://www.postgresql.org/docs/current/static/sql-copy.html > > > COPY stops operation at the first error. This should not lead to problems > in the event of a COPY TO, but the target table will already have > received earlier rows in a COPY FROM. These rows will not be visible or > accessible, but they still occupy disk space. This might amount to a > considerable amount of wasted disk space if the failure happened well into > a large copy operation. You might wish to invoke VACUUM to recover the > wasted space. > > does that mean that I should always execute a VACUUM to recover the wasted > space when an error is triggered or will the auto-vacuum mechanism do the > job by itself ? > > Thanks > Jerome > *>but the target table will already have received earlier rows in a COPY FROM* *No, that is not what happens. The entire copy is not permanently written to disk until a COMMIT or the entire statement is completed (;). On first error, a ROLLBACK is done so there is no wasted space. That being said, it is always good practice to schedule a VACUUM ANALYZE (but not FULL) in the off hours to insure a cleanup and fresh statistics. * -- *Melvin Davidson* I reserve the right to fantasize. Whether or not you wish to share my fantasy is entirely up to you.
