Re: TABLESAMPLE usage

On 01/25/2016 09:55 AM, Tom Smith wrote:
> Thanks, the solution would work for fixed interval timestamp.
> But the data I am dealing with has irregular timestamp so can not be
> generated with exact steps.
>
> I would consider this a special case/method of random sampling, evenly
> distributed sampling according to the defined  timestamp index.

You could probably create your own sampling method to do what you want.

See contrib modules tsm_system_rows and tsm_system_time for guidance.
http://www.postgresql.org/docs/current/static/tsm-system-rows.html
http://www.postgresql.org/docs/current/static/tsm-system-time.html
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Vik Fearing                                          +33 6 46 75 15 36
http://2ndQuadrant.fr     PostgreSQL : Expertise, Formation et Support