On 12 August 2016 at 16:23, Tom Lane <t...@sss.pgh.pa.us> wrote: > Simon Riggs <si...@2ndquadrant.com> writes: >> But now you mention it, I agree with you. Let's put it back to say >> "sample" but also explain where that new sample comes from... my >> attempt to explain this better is in square brackets > >> "If REPEATABLE is not given then a new random sample will be taken for >> each query [based upon the global seed value for the current user.]" > > I think "global" might have implications we don't want. How about > adding ", based on a system-generated seed"?
What I was trying to express was that SELECT setseed(dp); SELECT * FROM foo TABLESAMPLE ...; SELECT * FROM foo TABLESAMPLE ...; SELECT * FROM foo TABLESAMPLE ...; would yield a repeatable set of samples, similarly repeatable but not same samples as SELECT * FROM foo TABLESAMPLE ... REPEATABLE; SELECT * FROM foo TABLESAMPLE ... REPEATABLE; SELECT * FROM foo TABLESAMPLE ... REPEATABLE; so that people understand there is some predictability even without REPEATABLE. So I don't understand the "based on a system-generated seed", but maybe I'm missing information. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services -- Sent via pgsql-docs mailing list (pgsql-docs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-docs
