Re: Regarding Copy in postgresql

Dear Daniel Staal,

Thanks for your update.Now i could understand why it became out of
order.I used copy command to copy the data from text file into
database.These rows did not have a primary key attached to it.Hence i
made an autogenerate column and dumped the data to it.Here I used the
select statement and this is why the out of order copying of rows took
place.

Thanks for your insight.

Regards
Sree aurovindh V

On Thu, Mar 22, 2012 at 10:50 AM, Daniel Staal <DStaal(at)usa(dot)net> wrote
> --As of March 22, 2012 9:56:37 AM +0530, sreeaurovindh viswanathan is
> alleged to have said:
>
>> I have a text file which has about 140 million records spaced by tab.I
>> am trying it to read and put it into database.I have used Copy to do
>> it.For the delimiter i tried with \t but it did not work.Hence i
>> copied the tab space and pasted it in copy command and then it
>> executed.Does the copy command read the file sequentially.Atleast from
>> the ordering that i got it doesn't seem so.. If that is the case how
>> is the orderering of read..
>
>
> --As for the rest, it is mine.
>
> The copy itself should read the file sequentially, I think.  (I can't think
> of a single good reason not to do so from a programming standpoint.) However
> a 'select' to pull the data back out of the database is inherently
> unordered; it's order will have no relation (except by chance) to the order
> the data was put into the database.
>
> If you need to know if all of the data in the text file were loaded, it
> would be best to either count the records inserted, or select the last
> record and see if it was loaded.  If you need a more predictable way to find
> which was the last record read, you will either need to use the count
> (again), or to find some ordering in the text file that you can use in an
> 'order by' clause.  (If you are are on a Unix-like platform, it may be worth
> feeding your text file through `sort` just for this purpose.)
>
> Daniel T. Staal
>
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