1. 10 1月, 2007 5 次提交
  2. 09 1月, 2007 9 次提交
    • T
      Add a citation to Seltzer and Yigit's Usenix '91 paper about hash table · 69db0091
      Tom Lane 提交于
      management.  The paper clearly describes many of the ideas embodied in
      our current hashing code, but as far as I could find out there is not
      a direct code heritage.  (Mike Olsen recalls discussion of this paper
      at Postgres meetings but believes it "informed the Postgres implementation
      probably just at the design level".  Margo herself says she wasn't
      involved with Postgres' hash code.)  Credit where credit is due 'n all
      that, even if fifteen years after the fact.
      69db0091
    • T
      352871c3
    • T
      vcbuild documentation from Magnus and Dave. · 7d5d06f8
      Tom Lane 提交于
      7d5d06f8
    • B
      Done: · b0452cd8
      Bruce Momjian 提交于
      < * Allow the creation of indexes with mixed ascending/descending
      > * -Allow the creation of indexes with mixed ascending/descending
      <
      <   This is possible now by creating an operator class with reversed sort
      <   operators.  One complexity is that NULLs would then appear at the start
      <   of the result set, and this might affect certain sort types, like
      <   merge join.
      <
      b0452cd8
    • T
    • T
      Support ORDER BY ... NULLS FIRST/LAST, and add ASC/DESC/NULLS FIRST/NULLS LAST · 44317582
      Tom Lane 提交于
      per-column options for btree indexes.  The planner's support for this is still
      pretty rudimentary; it does not yet know how to plan mergejoins with
      nondefault ordering options.  The documentation is pretty rudimentary, too.
      I'll work on improving that stuff later.
      
      Note incompatible change from prior behavior: ORDER BY ... USING will now be
      rejected if the operator is not a less-than or greater-than member of some
      btree opclass.  This prevents less-than-sane behavior if an operator that
      doesn't actually define a proper sort ordering is selected.
      44317582
    • P
      Prevent duplicate attribute names in XMLELEMENT. · 3a32ba2f
      Peter Eisentraut 提交于
      3a32ba2f
    • T
      Tweak joinlist creation to avoid generating useless one-element subproblems · 19f9376b
      Tom Lane 提交于
      when collapsing of JOIN trees is stopped by join_collapse_limit.  For instance
      a list of 11 LEFT JOINs with limit 8 now produces something like
      	((1 2 3 4 5 6 7 8) 9 10 11 12)
      instead of
      	(((1 2 3 4 5 6 7 8) (9)) 10 11 12)
      The latter structure is really only required for a FULL JOIN.
      Noted while studying an example from Shane Ambler.
      19f9376b
    • T
      Remove cost_hashjoin's very ancient hack to discourage (once, entirely forbid) · 9a9a143a
      Tom Lane 提交于
      hash joins with the estimated-larger relation on the inside.  There are
      several cases where doing that makes perfect sense, and in cases where it
      doesn't, the regular cost computation really ought to be able to figure that
      out.  Make some marginal tweaks in said computation to try to get results
      approximating reality a bit better.  Per an example from Shane Ambler.
      
      Also, fix an oversight in the original patch to add seq_page_cost: the costs
      of spilling a hash join to disk should be scaled by seq_page_cost.
      9a9a143a
  3. 08 1月, 2007 2 次提交
  4. 07 1月, 2007 14 次提交
  5. 06 1月, 2007 10 次提交