Small improvement to get_base_rel_indexes()
Attached is a small patch which improves the way get_base_rel_indexes()
works.
The current version creates a new bitmapset on each recursion level then
bms_joins() to the one on the next level up each time. I understand that
this will patch will have about a 0 net performance improvement, but I
thought I'd post anyway as:
1. It removes 5 lines of code.
2. It's a better example to leave in the code.
Is it worth applying?
Regards
David Rowley
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Attachments:
get_base_rel_indexes_cleanup.difftext/plain; charset=US-ASCII; name=get_base_rel_indexes_cleanup.diffDownload+9-14
David Rowley <david.rowley@2ndquadrant.com> writes:
Attached is a small patch which improves the way get_base_rel_indexes()
works.
The current version creates a new bitmapset on each recursion level then
bms_joins() to the one on the next level up each time. I understand that
this will patch will have about a 0 net performance improvement, but I
thought I'd post anyway as:
1. It removes 5 lines of code.
2. It's a better example to leave in the code.
I don't know that it's a better example: it seems substantially uglier.
(Notably, you complicated the API contract of get_base_rel_indexes()
without documenting the fact: it's now dependent on the original caller
to have initialized *result to NULL.)
We might have to use a method like this if the function were returning
multiple sets; but since it is not, the existing approach seems more
readable and safer to me.
regards, tom lane
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