This is my first attempt at writing a patch, so it's pretty simple.
Commit log sums it up:
Adds a convenience feature to the explain command which prints out GUC cost parameters in explain text output.
For example:
explain (params) select * from table;
will include text output like the following:
Cost Params:
seq_page: 1.000000, rnd_page: 4.000000, cpu_tup: 0.010000, cpu_ind: 0.005000, cpu_op: 0.002500
amenabled: 11111111111
The bit vector is enable variables in the order listed in cost.h, though mainly provides a high level view on whether or not any strategies are disabled.
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I recognize that this is kind of a frivolous feature which may not be worth any potential maintenance burden, so submitted for what it's worth as an initial effort.
Best Regards,
Robert