Horton

Re: multivariate statistics (v19)

Alvaro Herrera <alvherre@2ndquadrant.com>

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From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: Dilip Kumar <dilipbalaut@gmail.com>, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, Dean Rasheed <dean.a.rasheed@gmail.com>, Heikki Linnakangas <hlinnaka@iki.fi>, Michael Paquier <michael.paquier@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Tatsuo Ishii <ishii@postgresql.org>, David Steele <david@pgmasters.net>, Tom Lane <tgl@sss.pgh.pa.us>, Petr Jelinek <petr@2ndquadrant.com>, Jeff Janes <jeff.janes@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2017-01-30T16:55:55Z
Lists: pgsql-hackers 
Minor nitpicks:

Let me suggest to use get_attnum() in CreateStatistics instead of
SearchSysCacheAttName for each column.  Also, we use type AttrNumber for
attribute numbers rather than int16.  Finally in the same function you
have an erroneous ERRCODE_UNDEFINED_COLUMN which should be
ERRCODE_DUPLICATE_COLUMN in the loop that searches for duplicates.

May I suggest that compare_int16 be named attnum_cmp (just to be
consistent with other qsort comparators) and look like
	return *((const AttrNumber *) a) - *((const AttrNumber *) b);
instead of memcmp?

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Collect and use multi-column dependency stats

  2. Implement SortSupport for macaddr data type

  3. Implement multivariate n-distinct coefficients

  4. Generate fmgr prototypes automatically