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Rethink the order of expression preprocessing: eval_const_expressions

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really ought to run before canonicalize_qual, because it can now produce
forms that canonicalize_qual knows how to improve (eg, NOT clauses).
Also, because eval_const_expressions already knows about flattening
nested ANDs and ORs into N-argument form, the initial flatten_andors
pass in canonicalize_qual is now completely redundant and can be
removed.  This doesn't save a whole lot of code, but the time and
palloc traffic eliminated is a useful gain on large expression trees.
This commit is contained in:
Tom Lane
2005-03-28 00:58:26 +00:00
parent bf3dbb5881
commit 5db2e83852
7 changed files with 61 additions and 140 deletions
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9
src/backend/optimizer/util/clauses.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.189 2005/03/27 19:18:02 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.190 2005/03/28 00:58:24 tgl Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@ -1190,6 +1190,9 @@ rowtype_field_matches(Oid rowtypeid, int fieldnum,
*
* We assume that the tree has already been type-checked and contains
* only operators and functions that are reasonable to try to execute.
*
* NOTE: the planner assumes that this will always flatten nested AND and
* OR clauses into N-argument form. See comments in prepqual.c.
*--------------------
*/
Node *
@ -1871,7 +1874,7 @@ eval_const_expressions_mutator(Node *node,
* is TRUE and at least one is NULL.
*
* This is split out as a subroutine so that we can recurse to fold sub-ORs
* into the upper OR clause, thereby preserving AND/OR flatness.
* into the upper OR clause, thereby ensuring that nested ORs are flattened.
*
* The output arguments *haveNull and *forceTrue must be initialized FALSE
* by the caller. They will be set TRUE if a null constant or true constant,
@ -1931,7 +1934,7 @@ simplify_or_arguments(List *args, bool *haveNull, bool *forceTrue)
* is FALSE and at least one is NULL.
*
* This is split out as a subroutine so that we can recurse to fold sub-ANDs
* into the upper AND clause, thereby preserving AND/OR flatness.
* into the upper AND clause, thereby ensuring that nested ANDs are flattened.
*
* The output arguments *haveNull and *forceFalse must be initialized FALSE
* by the caller. They will be set TRUE if a null constant or false constant,

4
src/backend/optimizer/util/restrictinfo.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/restrictinfo.c,v 1.31 2004/12/31 22:00:23 pgsql Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/restrictinfo.c,v 1.32 2005/03/28 00:58:24 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -63,7 +63,7 @@ make_restrictinfo(Expr *clause, bool is_pushed_down, bool valid_everywhere)
}
else
{
/* Shouldn't be an AND clause, else flatten_andors messed up */
/* Shouldn't be an AND clause, else AND/OR flattening messed up */
Assert(!and_clause((Node *) clause));
orclause = NULL;