postgresql/src/include/executor/nodeSubplan.h

/*-------------------------------------------------------------------------
 *
 * nodeSubplan.h
 *
 *
 *
 * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * $PostgreSQL: pgsql/src/include/executor/nodeSubplan.h,v 1.29 2009/01/01 17:23:59 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#ifndef NODESUBPLAN_H
#define NODESUBPLAN_H

#include "nodes/execnodes.h"

extern SubPlanState *ExecInitSubPlan(SubPlan *subplan, PlanState *parent);

extern AlternativeSubPlanState *ExecInitAlternativeSubPlan(AlternativeSubPlan *asplan, PlanState *parent);

extern void ExecReScanSetParamPlan(SubPlanState *node, PlanState *parent);

extern void ExecSetParamPlan(SubPlanState *node, ExprContext *econtext);

#endif   /* NODESUBPLAN_H */
Subselects... 1998-02-13 04:46:56 +01:00			`/*-------------------------------------------------------------------------`
			`*`
Change my-function-name-- to my_function_name, and optimizer renames. 1999-02-14 00:22:53 +01:00			`* nodeSubplan.h`
Subselects... 1998-02-13 04:46:56 +01:00			`*`
Phase 1 of read-only-plans project: cause executor state nodes to point to plan nodes, not vice-versa. All executor state nodes now inherit from struct PlanState. Copying of plan trees has been simplified by not storing a list of SubPlans in Plan nodes (eliminating duplicate links). The executor still needs such a list, but it can build it during ExecutorStart since it has to scan the plan tree anyway. No initdb forced since no stored-on-disk structures changed, but you will need a full recompile because of node-numbering changes. 2002-12-05 16:50:39 +01:00			`*`
			`*`
Update copyright for 2009. 2009-01-01 18:24:05 +01:00			`* Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group`
Phase 1 of read-only-plans project: cause executor state nodes to point to plan nodes, not vice-versa. All executor state nodes now inherit from struct PlanState. Copying of plan trees has been simplified by not storing a list of SubPlans in Plan nodes (eliminating duplicate links). The executor still needs such a list, but it can build it during ExecutorStart since it has to scan the plan tree anyway. No initdb forced since no stored-on-disk structures changed, but you will need a full recompile because of node-numbering changes. 2002-12-05 16:50:39 +01:00			`* Portions Copyright (c) 1994, Regents of the University of California`
			`*`
Update copyright for 2009. 2009-01-01 18:24:05 +01:00			`* $PostgreSQL: pgsql/src/include/executor/nodeSubplan.h,v 1.29 2009/01/01 17:23:59 momjian Exp $`
Phase 1 of read-only-plans project: cause executor state nodes to point to plan nodes, not vice-versa. All executor state nodes now inherit from struct PlanState. Copying of plan trees has been simplified by not storing a list of SubPlans in Plan nodes (eliminating duplicate links). The executor still needs such a list, but it can build it during ExecutorStart since it has to scan the plan tree anyway. No initdb forced since no stored-on-disk structures changed, but you will need a full recompile because of node-numbering changes. 2002-12-05 16:50:39 +01:00			`*`
Subselects... 1998-02-13 04:46:56 +01:00			`*-------------------------------------------------------------------------`
			`*/`
			`#ifndef NODESUBPLAN_H`
			`#define NODESUBPLAN_H`

Phase 1 of read-only-plans project: cause executor state nodes to point to plan nodes, not vice-versa. All executor state nodes now inherit from struct PlanState. Copying of plan trees has been simplified by not storing a list of SubPlans in Plan nodes (eliminating duplicate links). The executor still needs such a list, but it can build it during ExecutorStart since it has to scan the plan tree anyway. No initdb forced since no stored-on-disk structures changed, but you will need a full recompile because of node-numbering changes. 2002-12-05 16:50:39 +01:00			`#include "nodes/execnodes.h"`
Subselects... 1998-02-13 04:46:56 +01:00
Get rid of the separate EState for subplans, and just let them share the parent query's EState. Now that there's a single flat rangetable for both the main plan and subplans, there's no need anymore for a separate EState, and removing it allows cleaning up some crufty code in nodeSubplan.c and nodeSubqueryscan.c. Should be a tad faster too, although any difference will probably be hard to measure. This is the last bit of subsidiary mop-up work from changing to a flat rangetable. 2007-02-27 02:11:26 +01:00			`extern SubPlanState ExecInitSubPlan(SubPlan subplan, PlanState *parent);`
Arrange to convert EXISTS subqueries that are equivalent to hashable IN subqueries into the same thing you'd have gotten from IN (except always with unknownEqFalse = true, so as to get the proper semantics for an EXISTS). I believe this fixes the last case within CVS HEAD in which an EXISTS could give worse performance than an equivalent IN subquery. The tricky part of this is that if the upper query probes the EXISTS for only a few rows, the hashing implementation can actually be worse than the default, and therefore we need to make a cost-based decision about which way to use. But at the time when the planner generates plans for subqueries, it doesn't really know how many times the subquery will be executed. The least invasive solution seems to be to generate both plans and postpone the choice until execution. Therefore, in a query that has been optimized this way, EXPLAIN will show two subplans for the EXISTS, of which only one will actually get executed. There is a lot more that could be done based on this infrastructure: in particular it's interesting to consider switching to the hash plan if we start out using the non-hashed plan but find a lot more upper rows going by than we expected. I have therefore left some minor inefficiencies in place, such as initializing both subplans even though we will currently only use one. 2008-08-22 02:16:04 +02:00
			`extern AlternativeSubPlanState ExecInitAlternativeSubPlan(AlternativeSubPlan asplan, PlanState *parent);`
Get rid of the separate EState for subplans, and just let them share the parent query's EState. Now that there's a single flat rangetable for both the main plan and subplans, there's no need anymore for a separate EState, and removing it allows cleaning up some crufty code in nodeSubplan.c and nodeSubqueryscan.c. Should be a tad faster too, although any difference will probably be hard to measure. This is the last bit of subsidiary mop-up work from changing to a flat rangetable. 2007-02-27 02:11:26 +01:00
Another pgindent run with updated typedefs. 2003-08-08 23:42:59 +02:00			`extern void ExecReScanSetParamPlan(SubPlanState node, PlanState parent);`
Phase 1 of read-only-plans project: cause executor state nodes to point to plan nodes, not vice-versa. All executor state nodes now inherit from struct PlanState. Copying of plan trees has been simplified by not storing a list of SubPlans in Plan nodes (eliminating duplicate links). The executor still needs such a list, but it can build it during ExecutorStart since it has to scan the plan tree anyway. No initdb forced since no stored-on-disk structures changed, but you will need a full recompile because of node-numbering changes. 2002-12-05 16:50:39 +01:00
Another pgindent run with updated typedefs. 2003-08-08 23:42:59 +02:00			`extern void ExecSetParamPlan(SubPlanState node, ExprContext econtext);`
Another pgindent run. Fixes enum indenting, and improves #endif spacing. Also adds space for one-line comments. 2001-10-28 07:26:15 +01:00
New pgindent run with fixes suggested by Tom. Patch manually reviewed, initdb/regression tests pass. 2001-11-05 18:46:40 +01:00			`#endif /* NODESUBPLAN_H */`