On 10/20/2015 05:59 PM, Tom Lane wrote:
Robert Haas <robertmh...@gmail.com> writes:
On Tue, Oct 20, 2015 at 10:51 AM, Tomas Vondra
<tomas.von...@2ndquadrant.com> wrote:
ISTM that we could use COLLECT STATISTICS instead of ADD STATISTICS, and
use REMOVE STATISTICS instead of DROP STATISTICS. That way we can use
ALTER TABLE rather than inventing a new command. 5 minute change...
That seems like a neat idea, actually. I'm not sure COLLECT is a good choice
as it suggest the statistics is actually built, but that only happens during
ANALYZE. But otherwise this seems to solve the issues with keywords and it's
quite simple.
But ADD is no better there. I think ALTER TABLE .. COLLECT STATISTICS
isn't any worse than ALTER TABLE ... CLUSTER ON index_name. In both
cases, it means, when you do this operation, do it this way.
I would suggest that instead of DROP or REMOVE, the opposite should be
ALTER TABLE .. NO COLLECT STATISTICS.
Why is this an improvement over using already-existing keywords?
The problem is that the actual syntax is ADD [COLUMN], so we can't
simply use ADD STATISTICS as that would mean a conflict in the grammar.
Resolving it means either making COLUMN non-optional, or adding
STATISTICS to reserved keywords - both options break existing code.
regards
--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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