Re: pg_sample - Mailing list pgsql-general

On 08/27/2018 08:33 AM, Naveen Dabas wrote:
> actually i want limited data from the postgres database. But i don't 
> want to use .csv

Does the sample need to include parent/child relationships?

In Postgres 9.5+ there is TABLESAMPLE:

https://www.postgresql.org/docs/10/static/sql-select.html

So you can do something like:

select * from plant1 TABLESAMPLE system (25);

on a single table.

I could see doing the above in a program and INSERTing the output to 
another database.

> 
> 
> 
> thanks
> 
> On Mon, Aug 27, 2018 at 7:42 PM, Adrian Klaver 
> <adrian.klaver@aklaver.com <mailto:adrian.klaver@aklaver.com>> wrote:
> 
>     On 08/26/2018 11:03 PM, Naveen Dabas wrote:
> 
>         Server encoding is UTF8
>         Client encoding is UTF8
>         Creating sample schema sampledb1
>         DBD::Pg::db do failed: ERROR:  cannot execute CREATE SCHEMA in a
>         read-only transaction at ./pg_sample line 296.
>         main::__ANON__('DBD::Pg::db do failed: ERROR:  cannot execute
>         CREATE SCHEMA i...', 'DBI::db=HASH(0xab2388)', undef) called at
>         ./pg_sample line 478
>         Done.
> 
> 
>         can you help me in this
> 
> 
>     Yes, by suggesting you try something other then pg_sample. The last
>     commit was 4 years ago and it does not seem to be up to date enough.
> 
>     What sort of sampling do you want to do?
> 
>         thanks
> 
> 
>         On Mon, Aug 27, 2018 at 11:16 AM, Naveen Dabas
>         <naveen@paymonk.com <mailto:naveen@paymonk.com>
>         <mailto:naveen@paymonk.com <mailto:naveen@paymonk.com>>> wrote:
> 
>              Thanks for the help.
>              But now i'm getting some different error as i rum this command
>              ./pg_sample -a -f file.sql --limit="user = 100"
>         --schema=dbname -h
>              hostname -U user -W password
> 
>              I am not getting output and one file opens , in that file
>         there id
>              guide for pg_sample
>              ----
>              /tmp/9REOT5C
> 
>              NAME
>              pg_sample - extract a small, sample dataset from a larger
>         PostgreSQL
>              database while maintaining referential integrity.
>              =head1 SYNOPSIS
>              pg_sample [ option... ] [ dbname ]
>              =head1 DESCRIPTION
>              pg_sample is a utility for exporting a small, sample
>         dataset from a
>              larger PostgreSQL database. The output and command-line
>         options closely
>              resemble the pg_dump backup utility (although only the
>         plain-text format
>              is supported).
>              The sample database produced includes all tables from the
>         original,
>              maintains referential integrity, and supports circular
>         dependencies.
>              To build an actual instance of the sample database, the
>         output of
>              this script
>              can be piped to the psql utility. For example, assuming we
>         have an
>              existing
>              PostgreSQL database named "mydb", a sample database could be
>              constructed with:
>                 createdb sampledb
>                 pg_sample mydb | psql sampledb
>              and so on .......
> 
>              On Mon, Aug 27, 2018 at 1:27 AM, Paul Carlucci
>              <paul.carlucci@gmail.com <mailto:paul.carlucci@gmail.com>
>         <mailto:paul.carlucci@gmail.com
>         <mailto:paul.carlucci@gmail.com>>> wrote:
> 
>                  sudo yum install perl-CPAN
> 
>                  Also do a "yum search perl-" and you should find most,
>         if not
>                  all what you need natively packaged for your particular
>         Linux
>                  distro.  You're better off just sticking with the
>         pre-packaged
>                  perl modules unless you specifically need something
>         special.
> 
>                  You'll find more modules if you also enable the EPEL
>         yum repo by
>                  setting enabled=1 in the first section of
>                  /etc/yum.repos.d/epel.conf and rerunning that yum
>         search command.
> 
>                  On Sun, Aug 26, 2018, 2:20 PM Naveen Dabas
>         <naveen@paymonk.com <mailto:naveen@paymonk.com>
>                  <mailto:naveen@paymonk.com
>         <mailto:naveen@paymonk.com>>> wrote:
> 
>                      Sir i'm getting error in both commands
> 
>                      [root@ip-88-8-8-17 ~]#  perl -MCPAN -e 'install
>         Bundle::DBI'
>                      Can't locate CPAN.pm in @INC (@INC contains:
>                      /usr/local/lib64/perl5 /usr/local/share/perl5
>                      /usr/lib64/perl5/vendor_perl
>         /usr/share/perl5/vendor_perl
>                      /usr/lib64/perl5 /usr/share/perl5 .).
>                      BEGIN failed--compilation aborted.
>                      [root@ip-88-8-8-17 ~]# perl -MCPAN -e 'install DBD::Pg'
>                      Can't locate CPAN.pm in @INC (@INC contains:
>                      /usr/local/lib64/perl5 /usr/local/share/perl5
>                      /usr/lib64/perl5/vendor_perl
>         /usr/share/perl5/vendor_perl
>                      /usr/lib64/perl5 /usr/share/perl5 .).
>                      BEGIN failed--compilation aborted.
> 
> 
> 
>                      operating system =CentOS Linux release 7.5.1804 (Core)
> 
>                      thanks
> 
> 
>                      On Fri, Aug 24, 2018 at 6:16 PM, Abhinav Mehta
>                      <abhinav@metarain.com <mailto:abhinav@metarain.com>
>         <mailto:abhinav@metarain.com <mailto:abhinav@metarain.com>>> wrote:
> 
>                          Solution, execute this on your linux terminal -
> 
>                          $ perl -MCPAN -e 'install Bundle::DBI'
>                          $ perl -MCPAN -e 'install DBD::Pg'
> 
>                           > On 24-Aug-2018, at 6:13 PM, Ravi Krishna
>                          <sravikrishna@aol.com
>         <mailto:sravikrishna@aol.com> <mailto:sravikrishna@aol.com
>         <mailto:sravikrishna@aol.com>>> wrote:
>                           >
>                           >>
>                           >> sir have taken pg_sample
>                           >> Now i want to run pg_sample with credential
>         but i'm
>                          getting this error
>                           >>
>                           >> Can't locate DBI.pm in @INC (@INC contains:
>                          /usr/local/lib64/perl5 /usr/local/share/perl5
>                          /usr/lib64/perl5/vendor_perl
>                          /usr/share/perl5/vendor_perl /usr/lib64/perl5
>                          /usr/share/perl5 .) at ./pg_sample line 192.
>                           >> BEGIN failed--compilation aborted at
>         ./pg_sample
>                          line 192.
>                           >
>                           > As is clear from the message, you need to
>         install
>                          Perl DBI/DBD first.
>                           >
>                           >
> 
> 
> 
> 
>                      --             --
>                      With Regards
>                      Naveen Dabas
>                      Ph. 9017298370
> 
> 
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> 
> 
> 
>              --     --
>              With Regards
>              Naveen Dabas
>              Ph. 9017298370
> 
> 
> 
> 
>         -- 
>         --
>         With Regards
>         Naveen Dabas
>         Ph. 9017298370
> 
> 
>         *Important Disclaimer:* Information contained in this email is
>         for the recipient primarily addressed to. If you are not the
>         primary recipient or are not supposed to receive this email, you
>         are advised to kindly delete the email or the thread and notify
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> 
> 
> 
>     -- 
>     Adrian Klaver
>     adrian.klaver@aklaver.com <mailto:adrian.klaver@aklaver.com>
> 
> 
> 
> 
> -- 
> --
> With Regards
> Naveen Dabas
> Ph. 9017298370
> 
> 
> *Important Disclaimer:* Information contained in this email is for the 
> recipient primarily addressed to. If you are not the primary recipient 
> or are not supposed to receive this email, you are advised to kindly 
> delete the email or the thread and notify of the error. The logo is a 
> registered and copyrighted property of *ACTAS TECHNOLOGIES PRIVATE 
> LIMITED*. Do not use it without authorization.


-- 
Adrian Klaver
adrian.klaver@aklaver.com