On 11/14/2016 9:25 PM, Mark Anns wrote:
I am just curious about this planning factors in GPU.
There can be more than one appropriate paths in query plan tree. How the
decision for particular path has been made considering those planning
factors?
the postgresql planner considers a number of alternate execution plans,
assigns each step of each plan a estimated cost and for each plan sums
up those costs, the plan with the lowest cost wins.
the documentation on EXPLAIN [1] [2] goes into the basics of planning.
Chapter 67 [3] goes into some more detail.
[1] https://www.postgresql.org/docs/current/static/using-explain.html
[2] https://www.postgresql.org/docs/current/static/planner-stats.html
[3]
https://www.postgresql.org/docs/current/static/row-estimation-examples.html
--
john r pierce, recycling bits in santa cruz
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