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IN clauses appearing at top level of WHERE can now be handled as joins.

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There are two implementation techniques: the executor understands a new
JOIN_IN jointype, which emits at most one matching row per left-hand row,
or the result of the IN's sub-select can be fed through a DISTINCT filter
and then joined as an ordinary relation.
Along the way, some minor code cleanup in the optimizer; notably, break
out most of the jointree-rearrangement preprocessing in planner.c and
put it in a new file prep/prepjointree.c.
This commit is contained in:
Tom Lane
2003-01-20 18:55:07 +00:00
parent be2b660ecd
commit bdfbfde1b1
47 changed files with 2075 additions and 875 deletions
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15
src/backend/utils/adt/selfuncs.c
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@ -15,7 +15,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.126 2003/01/15 19:35:44 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.127 2003/01/20 18:54:59 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1825,8 +1825,7 @@ mergejoinscansel(Query *root, Node *clause,
*
* Inputs:
* root - the query
* groupClauses - list of GroupClauses (or SortClauses for the DISTINCT
* case, but those are equivalent structs)
* groupExprs - list of expressions being grouped by
* input_rows - number of rows estimated to arrive at the group/unique
* filter step
*
@ -1867,7 +1866,7 @@ mergejoinscansel(Query *root, Node *clause,
* do better).
*/
double
estimate_num_groups(Query *root, List *groupClauses, double input_rows)
estimate_num_groups(Query *root, List *groupExprs, double input_rows)
{
List *allvars = NIL;
List *varinfos = NIL;
@ -1879,14 +1878,12 @@ estimate_num_groups(Query *root, List *groupClauses, double input_rows)
} MyVarInfo;
/* We should not be called unless query has GROUP BY (or DISTINCT) */
Assert(groupClauses != NIL);
Assert(groupExprs != NIL);
/* Step 1: get the unique Vars used */
foreach(l, groupClauses)
foreach(l, groupExprs)
{
GroupClause *grpcl = (GroupClause *) lfirst(l);
Node *groupexpr = get_sortgroupclause_expr(grpcl,
root->targetList);
Node *groupexpr = (Node *) lfirst(l);
List *varshere;
varshere = pull_var_clause(groupexpr, false);