Hi
2017-01-04 14:00 GMT+01:00 vod vos <vod...@zoho.com>:
> Now I am confused about I can create 1100 columns in a table in
> postgresql, but I can't copy 1100 values into the table. And I really dont
> want to split the csv file to pieces to avoid mistakes after this action.
>
The PostgreSQL limit is "Maximum Columns per Table250 - 1600 depending on
column types" - this limit is related to placing values or pointers to
values to one page (8KB).
You can hit this limit not in CREATE TABLE time, but in INSERT time.
>
> I create a table with 1100 columns with data type of varchar, and hope the
> COPY command will auto transfer the csv data that contains some character
> and date, most of which are numeric.
>
Numeric is expensive type - try to use float instead, maybe double.
Regards
Pavel
> I use the command: COPY rius FROM "/var/www/test/test.csv" WITH DELIMITER
> ';' ;
>
> Then it shows:
>
> ERROR: row is too big: size 11808, maximum size 8160
>
>
>
>
>
>
>
> ---- On 星期二, 03 一月 2017 05:24:18 -0800 *John McKown
> <john.archie.mck...@gmail.com <john.archie.mck...@gmail.com>>* wrote ----
>
> On Mon, Jan 2, 2017 at 2:57 PM, Rob Sargent <robjsarg...@gmail.com> wrote:
>
> Perhaps this is your opportunity to correct someone else's mistake. You
> need to show the table definition to convince us that it cannot be
> improved. That it may be hard work really doesn't mean it's not the right
> path.
>
>
> This may not be possible. The data might be coming in from an external
> source. I imagine you've run into the old "well, _we_ don't have any
> problems, so it must be on your end!" scenario.
>
> Example: we receive CSV files from an external source. These files are
> _supposed_ to be validated. But we have often received files where NOT NULL
> fields have "nothing" in them them. E.g. a customer bill which has
> _everything_ in it _except_ the customer number (or an invalid one such as
> "123{"); or missing some other vital piece of information.
>
> In this particular case, the OP might want to do what we did in a similar
> case. We had way too many columns in a table. The performance was horrible.
> We did an analysis and, as usual, the majority of the selects were for a
> subset of the columns, about 15% of the total. We "split" the table into
> the "high use" columns table & the "low use" columns table. We then used
> triggers to make sure that if we added a new / deleted an old row from one
> table, the corresponding row in the other was created / deleted.
>
>
>
>
>
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>
>
>
> --
> There’s no obfuscated Perl contest because it’s pointless.
>
> —Jeff Polk
>
> Maranatha! <><
> John McKown
>
>
>
