Re: speed up full table scan using psql

The whole command is:

psql %(pg_uri)s -c %(sql)s | %(sed)s | %(pv)s | %(split)s) 2>&1 | %(tr)s

where:
sql is "copy (select row_to_json(x_tmp_uniq) from public.mytable
x_tmp_uniq) to stdout"
sed, pv, split, tr together format and split the stdout into jsonl files.

Hope this helps.

On Wed, May 31, 2023 at 9:16 PM Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com>
wrote:

> On 5/31/23 13:57, Lian Jiang wrote:
> > The command is: psql $db_url -c "copy (select row_to_json(x_tmp_uniq)
> > from public.mytable x_tmp_uniq) to stdout"
>
> What is taking the stdout and what it is it doing?
>
> > postgres version: 14.7
> > Does this mean COPY and java CopyManager may not help since my psql
> > command already uses copy?
> >
> > Regarding pg_dump, it does not support json format which means extra
> > work is needed to convert the supported format to jsonl (or parquet) so
> > that they can be imported into snowflake. Still exploring but want to
> > call it out early. Maybe 'custom' format can be parquet?
> >
> >
> > Thanks
> > Lian
>
> --
> Adrian Klaver
> adrian(dot)klaver(at)aklaver(dot)com
>
>

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