database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-11-16 15:02:33 +03:00
Code Activity

Turn the rangetable used by the executor into a flat list, and avoid storing

Browse Source 
useless substructure for its RangeTblEntry nodes.  (I chose to keep using the
same struct node type and just zero out the link fields for unneeded info,
rather than making a separate ExecRangeTblEntry type --- it seemed too
fragile to have two different rangetable representations.)

Along the way, put subplans into a list in the toplevel PlannedStmt node,
and have SubPlan nodes refer to them by list index instead of direct pointers.
Vadim wanted to do that years ago, but I never understood what he was on about
until now.  It makes things a *whole* lot more robust, because we can stop
worrying about duplicate processing of subplans during expression tree
traversals.  That's been a constant source of bugs, and it's finally gone.

There are some consequent simplifications yet to be made, like not using
a separate EState for subplans in the executor, but I'll tackle that later.
This commit is contained in:
Tom Lane
2007-02-22 22:00:26 +00:00
parent 849000c782
commit eab6b8b27e
32 changed files with 841 additions and 1004 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
src/include/nodes/primnodes.h
View File

@@ -10,7 +10,7 @@
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/nodes/primnodes.h,v 1.126 2007/02/20 17:32:17 tgl Exp $
* $PostgreSQL: pgsql/src/include/nodes/primnodes.h,v 1.127 2007/02/22 22:00:25 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -428,8 +428,10 @@ typedef struct SubLink
* SubPlan - executable expression node for a subplan (sub-SELECT)
*
* The planner replaces SubLink nodes in expression trees with SubPlan
* nodes after it has finished planning the subquery. SubPlan contains
* a sub-plantree and rtable instead of a sub-Query.
* nodes after it has finished planning the subquery. SubPlan references
* a sub-plantree stored in the subplans list of the toplevel PlannedStmt.
* (We avoid a direct link to make it easier to copy expression trees
* without causing multiple processing of the subplan.)
*
* In an ordinary subplan, testexpr points to an executable expression
* (OpExpr, an AND/OR tree of OpExprs, or RowCompareExpr) for the combining
@@ -463,12 +465,10 @@ typedef struct SubPlan
/* The combining operators, transformed to an executable expression: */
Node *testexpr; /* OpExpr or RowCompareExpr expression tree */
List *paramIds; /* IDs of Params embedded in the above */
/* The subselect, transformed to a Plan: */
struct Plan *plan; /* subselect plan itself */
int plan_id; /* kluge because we haven't equal-funcs for
* plan nodes... we compare this instead of
* subselect plan */
List *rtable; /* range table for subselect */
/* Identification of the Plan tree to use: */
int plan_id; /* Index (from 1) in PlannedStmt.subplans */
/* Extra data saved for the convenience of exprType(): */
Oid firstColType; /* Type of first column of subplan result */
/* Information about execution strategy: */
bool useHashTable; /* TRUE to store subselect output in a hash
* table (implies we are doing "IN") */