SQLite: Check-in [92848623]

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Overview

Comment:	More details in the header comment of pushDownWhereTerms(). No changes to code.
Downloads:	Tarball \| ZIP archive \| SQL archive
Timelines:	family \| ancestors \| descendants \| both \| prefer-coroutine-sort-subquery
Files:	files \| file ages \| folders
SHA3-256:	928486231ff7cc0df17a5aa23a080a1b8720e168db5227a7dbd34861283ba689
User & Date:	drh 2017-09-30 11:47:06

Context

2017-10-02
02:52		The query planner now always prefers to implement a FROM-clause subquery using a co-routine rather than flattening the subquery into the outer query. check-in: c9104b59 user: drh tags: trunk
2017-09-30
11:47		More details in the header comment of pushDownWhereTerms(). No changes to code. Closed-Leaf check-in: 92848623 user: drh tags: prefer-coroutine-sort-subquery
10:50		Make sure the SQLITE_Stat34 optimization switch is always 0x800, a value which is hard-coded in the TH3 test suite. check-in: 6aed4ea3 user: drh tags: prefer-coroutine-sort-subquery

Changes

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Changes to src/select.c.

  3827   3827   ** The hope is that the terms added to the inner query will make it more
  3828   3828   ** efficient.
  3829   3829   **
  3830   3830   ** Do not attempt this optimization if:
  3831   3831   **
  3832   3832   **   (1) (** This restriction was removed on 2017-09-29.  We used to
  3833   3833   **           disallow this optimization for aggregate subqueries, but now
  3834         -**           it is allowed by putting the extra terms on the HAVING clause **)
         3834  +**           it is allowed by putting the extra terms on the HAVING clause.
         3835  +**           The added HAVING clause is pointless if the subquery lacks
         3836  +**           a GROUP BY clause.  But such a HAVING clause is also harmless
         3837  +**           so there does not appear to be any reason to add extra logic
         3838  +**           to suppress it. **)
  3835   3839   **
  3836   3840   **   (2) The inner query is the recursive part of a common table expression.
  3837   3841   **
  3838   3842   **   (3) The inner query has a LIMIT clause (since the changes to the WHERE
  3839   3843   **       close would change the meaning of the LIMIT).
  3840   3844   **
  3841   3845   **   (4) The inner query is the right operand of a LEFT JOIN.  (The caller