On 5/3/05, Tom Lane <[EMAIL PROTECTED]> wrote: > Steven Rosenstein <[EMAIL PROTECTED]> writes: > > My question is, are there any advantages, drawbacks, or outright > > restrictions to using multiple simultaneous COPY commands to load data into > > the same table? > > It will work; not sure about whether there is any performance benefit. > I vaguely recall someone having posted about doing this, so you might > check the archives. >
I may be one of Tom's vague "voices". ;) The only issue would be that you need to remove all you UNIQUE constraints before sending multiple COPYs to the server. This includes the PRIMARY KEY constraint. To the backend, COPY is just like INSERT and all constraints need to be checked and this will block the commit of one of the COPY streams. However, multiple COPYs may no be needed. I regularly load several table totaling around 50M rows with a single COPY per table. I drop (actually, this is during DB reload, so I don't yet create...) all fkeys, constraints and indexes and the data loads in a matter of 5 minutes or so. Hope that helps! -- Mike Rylander [EMAIL PROTECTED] GPLS -- PINES Development Database Developer http://open-ils.org ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
