Re: question on error during COPY FROM - Mailing list pgsql-general
On Tue, Aug 23, 2016 at 6:04 AM, Jerome Wagner <jerome.wagner@laposte.net> wrote:
Hello,in the documentation I readCOPY 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 ?ThanksJerome
>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
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I reserve the right to fantasize. Whether or not you
wish to share my fantasy is entirely up to you.
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