Tid access method feature from Hiroshi Inoue, Inoue@tpf.co.jp

src/backend/optimizer/path/tidpath.c

@@ -0,0 +1,296 @@
+/*-------------------------------------------------------------------------
+ *
+ * tidpath.c
+ *	  Routines to determine which tids are usable for scanning a
+ *	  given relation, and create TidPaths accordingly.
+ *
+ * Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/path/tidpath.c,v 1.1 1999/11/23 20:06:55 momjian Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#include <math.h>
+
+#include "postgres.h"
+
+#include "access/heapam.h"
+#include "catalog/catname.h"
+#include "catalog/pg_amop.h"
+#include "catalog/pg_operator.h"
+#include "executor/executor.h"
+#include "nodes/makefuncs.h"
+#include "nodes/nodeFuncs.h"
+#include "optimizer/clauses.h"
+#include "optimizer/cost.h"
+#include "optimizer/pathnode.h"
+#include "optimizer/paths.h"
+#include "optimizer/plancat.h"
+#include "optimizer/restrictinfo.h"
+#include "parser/parse_coerce.h"
+#include "parser/parse_expr.h"
+#include "parser/parse_oper.h"
+#include "parser/parsetree.h"
+#include "utils/lsyscache.h"
+
+static List	*create_tidscan_joinpaths(RelOptInfo *);
+static List	*TidqualFromRestrictinfo(List *relids, List * restrictinfo);
+static bool	isEvaluable(int varno, Node *node);
+static Node	*TidequalClause(int varno, Expr *node);
+static List	*TidqualFromExpr(int varno, Expr *expr);
+
+static
+bool isEvaluable(int varno, Node *node)
+{
+	List	*lst;
+	Expr	*expr;
+
+	if (IsA(node, Const))		return true;
+	if (IsA(node, Param))		return true;
+	if (IsA(node, Var))
+	{
+		Var	*var = (Var *)node;
+
+		if (var->varno == varno)
+			return false;
+		return true;
+	}
+	if (!is_funcclause(node))	return false;
+	expr = (Expr *)node;
+	foreach (lst, expr->args)
+	{
+		if (!isEvaluable(varno, lfirst(lst)))
+			return false;
+	}
+
+	return true;
+}
+
+/*
+ *	The 2nd parameter should be an opclause
+ *	Extract the right node if the opclause is CTID= ....
+ *	  or    the left  node if the opclause is ....=CTID
+ */
+static
+Node *TidequalClause(int varno, Expr *node)
+{
+	Node	*rnode = 0, *arg1, *arg2, *arg;
+	Oper	*oper;
+	Var	*var;
+	Const	*aconst;
+	Param	*param;
+	Expr	*expr;
+
+	if (!node->oper)		return rnode;
+	if (!node->args)		return rnode;
+	if (length(node->args) != 2)	return rnode;
+        oper = (Oper *) node->oper;
+	if (oper->opno != TIDEqualOperator)
+		return rnode;
+	arg1 = lfirst(node->args);
+	arg2 = lsecond(node->args);
+
+	arg = (Node *)0;
+	if (IsA(arg1, Var))
+	{
+		var = (Var *) arg1;
+		if (var->varno == varno &&
+		    var->varattno == SelfItemPointerAttributeNumber &&
+		    var->vartype == TIDOID)
+			arg = arg2;
+		else if (var->varnoold == varno &&
+		    	var->varoattno == SelfItemPointerAttributeNumber &&
+		    	var->vartype == TIDOID)
+			arg = arg2;
+	}
+	if ((!arg) && IsA(arg2, Var))
+	{
+		var = (Var *) arg2;
+		if (var->varno == varno &&
+		    var->varattno == SelfItemPointerAttributeNumber &&
+		    var->vartype == TIDOID)
+			arg = arg1;
+	}
+	if (!arg)
+		return rnode;
+	switch (nodeTag(arg))
+	{
+	 	case T_Const:
+			aconst = (Const *) arg;
+			if (aconst->consttype != TIDOID)
+				return rnode;
+			if (aconst->constbyval)
+				return rnode;
+			rnode = arg;
+			break;
+	 	case T_Param:
+			param = (Param *) arg;
+			if (param->paramtype != TIDOID)
+				return rnode;
+			rnode = arg;
+			break;
+	 	case T_Var:
+			var = (Var *) arg;
+			if (var->varno == varno ||
+			    var->vartype != TIDOID)
+				return rnode;
+			rnode = arg;
+			break;
+	 	case T_Expr:
+			expr = (Expr *) arg;
+			if (expr->typeOid != TIDOID)	return rnode;
+			if (expr->opType != FUNC_EXPR)	return rnode;
+			if (isEvaluable(varno, (Node *)expr))
+				rnode = arg;
+			break;
+	 	default:
+			break;
+	}
+	return rnode;
+}
+
+/*
+ *	Extract the list of CTID values from a specified expr node.
+ *	When the expr node is an or_clause,we try to extract CTID
+ *	values from all member nodes. However we would discard them
+ *	all if we couldn't extract CTID values from a member node.
+ *	When the expr node is an and_clause,we return the list of
+ *	CTID values if we could extract the CTID values from a member
+ *	node.
+ */ 
+static
+List *TidqualFromExpr(int varno, Expr *expr)
+{
+	List	*rlst = NIL, *lst, *frtn;
+	Node	*node = (Node *) expr, *rnode;
+
+	if (is_opclause(node))
+	{
+		rnode = TidequalClause(varno, expr);
+		if (rnode)
+		{
+			rlst = lcons(rnode, rlst);
+		} 
+	}
+	else if (and_clause(node))
+	{
+		foreach (lst, expr->args)
+		{
+			node = lfirst(lst);
+			if (!IsA(node, Expr))	
+				continue;
+			rlst = TidqualFromExpr(varno, (Expr *)node);
+			if (rlst)
+				break;
+		}
+	}
+	else if (or_clause(node))
+	{
+		foreach (lst, expr->args)
+		{
+			node = lfirst(lst);
+			if (IsA(node, Expr) &&
+			    (frtn = TidqualFromExpr(varno, (Expr *)node)) )
+			{
+				rlst = nconc(rlst, frtn);
+			}
+			else
+			{
+				if (rlst)
+					freeList(rlst);
+				rlst = NIL;
+				break;
+			}
+		}
+	}
+	return rlst;
+} 
+
+static
+List *TidqualFromRestrictinfo(List *relids, List * restrictinfo)
+{
+	List	*lst, *rlst = NIL;
+	int	varno;
+	Node	*node;
+	Expr	*expr;
+
+	if (length(relids)>1)	return NIL;
+	varno = (int)lfirst(relids);
+	foreach (lst, restrictinfo)
+	{
+		node = lfirst(lst);
+		if (!IsA(node, RestrictInfo))	continue;
+		expr = ((RestrictInfo *)node)->clause;
+		rlst = TidqualFromExpr(varno, expr);
+		if (rlst)
+		{
+			break;
+		}
+	}
+	return rlst;
+}
+
+/*
+ * create_tidscan_joinpaths
+ *	  Creates a path corresponding to a tid_direct scan, returning the
+ *	  pathnode.
+ *
+ */
+List *
+create_tidscan_joinpaths(RelOptInfo *rel)
+{
+	List		*rlst = NIL, *lst;
+	TidPath		*pathnode = (TidPath *)0;
+	List		*restinfo, *tideval;
+
+	foreach (lst, rel->joininfo)
+	{
+		JoinInfo *joininfo = (JoinInfo *)lfirst(lst);
+		restinfo = joininfo->jinfo_restrictinfo;
+		tideval = TidqualFromRestrictinfo(rel->relids, restinfo);
+		if (tideval && length(tideval) == 1)
+		{
+			pathnode = makeNode(TidPath);
+
+			pathnode->path.pathtype = T_TidScan;
+			pathnode->path.parent = rel;
+			pathnode->path.path_cost = 0.0;
+			pathnode->path.pathkeys = NIL;
+
+			pathnode->path.path_cost = cost_tidscan(tideval);
+			pathnode->tideval = tideval;
+			/*
+			pathnode->tideval = copyObject(tideval);
+			freeList(tideval);
+			*/
+			pathnode->unjoined_relids = joininfo->unjoined_relids;
+			rlst = lappend(rlst, pathnode);
+		}
+	}
+	rel->innerjoin = nconc(rel->innerjoin, rlst);
+	return rlst;
+}
+
+/*
+ * create_tidscan_paths
+ *	  Creates a path corresponding to a tid direct scan, returning the
+ *	  pathnode List.
+ *
+ */
+List *
+create_tidscan_paths(Query *root, RelOptInfo *rel)
+{
+	List	*rlst = NIL;
+	TidPath	*pathnode = (TidPath *)0;
+	List	*tideval = TidqualFromRestrictinfo(rel->relids, rel->restrictinfo);
+	
+	if (tideval)
+		pathnode = create_tidscan_path(rel, tideval);
+	if (pathnode)
+		rlst = lcons(pathnode, rlst);
+	create_tidscan_joinpaths(rel);
+
+	return rlst;
+}