analyze.c

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/*-------------------------------------------------------------------------
 *
 * analyze.c
 *	  transform the parse tree into a query tree
 *
 * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *	$PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.326.2.1 2005/11/22 18:23:12 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */

#include "postgres.h"

#include "access/heapam.h"
#include "catalog/heap.h"
#include "catalog/index.h"
#include "catalog/namespace.h"
#include "catalog/pg_index.h"
#include "catalog/pg_type.h"
#include "commands/defrem.h"
#include "commands/prepare.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/var.h"
#include "parser/analyze.h"
#include "parser/gramparse.h"
#include "parser/parsetree.h"
#include "parser/parse_agg.h"
#include "parser/parse_clause.h"
#include "parser/parse_coerce.h"
#include "parser/parse_expr.h"
#include "parser/parse_oper.h"
#include "parser/parse_relation.h"
#include "parser/parse_target.h"
#include "parser/parse_type.h"
#include "parser/parse_expr.h"
#include "rewrite/rewriteManip.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/relcache.h"
#include "utils/syscache.h"


/* State shared by transformCreateSchemaStmt and its subroutines */
typedef struct
{
	const char *stmtType;		/* "CREATE SCHEMA" or "ALTER SCHEMA" */
	char	   *schemaname;		/* name of schema */
	char	   *authid;			/* owner of schema */
	List	   *sequences;		/* CREATE SEQUENCE items */
	List	   *tables;			/* CREATE TABLE items */
	List	   *views;			/* CREATE VIEW items */
	List	   *indexes;		/* CREATE INDEX items */
	List	   *triggers;		/* CREATE TRIGGER items */
	List	   *grants;			/* GRANT items */
	List	   *fwconstraints;	/* Forward referencing FOREIGN KEY constraints */
	List	   *alters;			/* Generated ALTER items (from the above) */
	List	   *ixconstraints;	/* index-creating constraints */
	List	   *blist;			/* "before list" of things to do before
								 * creating the schema */
	List	   *alist;			/* "after list" of things to do after creating
								 * the schema */
} CreateSchemaStmtContext;

/* State shared by transformCreateStmt and its subroutines */
typedef struct
{
	const char *stmtType;		/* "CREATE TABLE" or "ALTER TABLE" */
	RangeVar   *relation;		/* relation to create */
	List	   *inhRelations;	/* relations to inherit from */
	bool		hasoids;		/* does relation have an OID column? */
	bool		isalter;		/* true if altering existing table */
	List	   *columns;		/* ColumnDef items */
	List	   *ckconstraints;	/* CHECK constraints */
	List	   *fkconstraints;	/* FOREIGN KEY constraints */
	List	   *ixconstraints;	/* index-creating constraints */
	List	   *blist;			/* "before list" of things to do before
								 * creating the table */
	List	   *alist;			/* "after list" of things to do after creating
								 * the table */
	IndexStmt  *pkey;			/* PRIMARY KEY index, if any */
} CreateStmtContext;

typedef struct
{
	Oid		   *paramTypes;
	int			numParams;
} check_parameter_resolution_context;


static List *do_parse_analyze(Node *parseTree, ParseState *pstate);
static Query *transformStmt(ParseState *pstate, Node *stmt,
			  List **extras_before, List **extras_after);
static Query *transformViewStmt(ParseState *pstate, ViewStmt *stmt,
				  List **extras_before, List **extras_after);
static Query *transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt);
static Query *transformInsertStmt(ParseState *pstate, InsertStmt *stmt,
					List **extras_before, List **extras_after);
static Query *transformIndexStmt(ParseState *pstate, IndexStmt *stmt);
static Query *transformRuleStmt(ParseState *query, RuleStmt *stmt,
				  List **extras_before, List **extras_after);
static Query *transformSelectStmt(ParseState *pstate, SelectStmt *stmt);
static Query *transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt);
static Node *transformSetOperationTree(ParseState *pstate, SelectStmt *stmt);
static Query *transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt);
static Query *transformDeclareCursorStmt(ParseState *pstate,
						   DeclareCursorStmt *stmt);
static Query *transformPrepareStmt(ParseState *pstate, PrepareStmt *stmt);
static Query *transformExecuteStmt(ParseState *pstate, ExecuteStmt *stmt);
static Query *transformCreateStmt(ParseState *pstate, CreateStmt *stmt,
					List **extras_before, List **extras_after);
static Query *transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt,
						List **extras_before, List **extras_after);
static void transformColumnDefinition(ParseState *pstate,
						  CreateStmtContext *cxt,
						  ColumnDef *column);
static void transformTableConstraint(ParseState *pstate,
						 CreateStmtContext *cxt,
						 Constraint *constraint);
static void transformInhRelation(ParseState *pstate, CreateStmtContext *cxt,
					 InhRelation *inhrelation);
static void transformIndexConstraints(ParseState *pstate,
						  CreateStmtContext *cxt);
static void transformFKConstraints(ParseState *pstate,
					   CreateStmtContext *cxt,
					   bool skipValidation,
					   bool isAddConstraint);
static void applyColumnNames(List *dst, List *src);
static List *getSetColTypes(ParseState *pstate, Node *node);
static void transformLockingClause(Query *qry, LockingClause *lc);
static void transformConstraintAttrs(List *constraintList);
static void transformColumnType(ParseState *pstate, ColumnDef *column);
static void release_pstate_resources(ParseState *pstate);
static FromExpr *makeFromExpr(List *fromlist, Node *quals);
static bool check_parameter_resolution_walker(Node *node,
								check_parameter_resolution_context *context);


/*
 * parse_analyze
 *		Analyze a raw parse tree and transform it to Query form.
 *
 * Optionally, information about $n parameter types can be supplied.
 * References to $n indexes not defined by paramTypes[] are disallowed.
 *
 * The result is a List of Query nodes (we need a list since some commands
 * produce multiple Queries).  Optimizable statements require considerable
 * transformation, while many utility-type statements are simply hung off
 * a dummy CMD_UTILITY Query node.
 */
List *
parse_analyze(Node *parseTree, Oid *paramTypes, int numParams)
{
	ParseState *pstate = make_parsestate(NULL);
	List	   *result;

	pstate->p_paramtypes = paramTypes;
	pstate->p_numparams = numParams;
	pstate->p_variableparams = false;

	result = do_parse_analyze(parseTree, pstate);

	pfree(pstate);

	return result;
}

/*
 * parse_analyze_varparams
 *
 * This variant is used when it's okay to deduce information about $n
 * symbol datatypes from context.  The passed-in paramTypes[] array can
 * be modified or enlarged (via repalloc).
 */
List *
parse_analyze_varparams(Node *parseTree, Oid **paramTypes, int *numParams)
{
	ParseState *pstate = make_parsestate(NULL);
	List	   *result;

	pstate->p_paramtypes = *paramTypes;
	pstate->p_numparams = *numParams;
	pstate->p_variableparams = true;

	result = do_parse_analyze(parseTree, pstate);

	*paramTypes = pstate->p_paramtypes;
	*numParams = pstate->p_numparams;

	pfree(pstate);

	/* make sure all is well with parameter types */
	if (*numParams > 0)
	{
		check_parameter_resolution_context context;

		context.paramTypes = *paramTypes;
		context.numParams = *numParams;
		check_parameter_resolution_walker((Node *) result, &context);
	}

	return result;
}

/*
 * parse_sub_analyze
 *		Entry point for recursively analyzing a sub-statement.
 */
List *
parse_sub_analyze(Node *parseTree, ParseState *parentParseState)
{
	ParseState *pstate = make_parsestate(parentParseState);
	List	   *result;

	result = do_parse_analyze(parseTree, pstate);

	pfree(pstate);

	return result;
}

/*
 * do_parse_analyze
 *		Workhorse code shared by the above variants of parse_analyze.
 */
static List *
do_parse_analyze(Node *parseTree, ParseState *pstate)
{
	List	   *result = NIL;

	/* Lists to return extra commands from transformation */
	List	   *extras_before = NIL;
	List	   *extras_after = NIL;
	Query	   *query;
	ListCell   *l;

	query = transformStmt(pstate, parseTree, &extras_before, &extras_after);

	/* don't need to access result relation any more */
	release_pstate_resources(pstate);

	foreach(l, extras_before)
		result = list_concat(result, parse_sub_analyze(lfirst(l), pstate));

	result = lappend(result, query);

	foreach(l, extras_after)
		result = list_concat(result, parse_sub_analyze(lfirst(l), pstate));

	/*
	 * Make sure that only the original query is marked original. We have to
	 * do this explicitly since recursive calls of do_parse_analyze will have
	 * marked some of the added-on queries as "original".  Also mark only the
	 * original query as allowed to set the command-result tag.
	 */
	foreach(l, result)
	{
		Query	   *q = lfirst(l);

		if (q == query)
		{
			q->querySource = QSRC_ORIGINAL;
			q->canSetTag = true;
		}
		else
		{
			q->querySource = QSRC_PARSER;
			q->canSetTag = false;
		}
	}

	return result;
}

static void
release_pstate_resources(ParseState *pstate)
{
	if (pstate->p_target_relation != NULL)
		heap_close(pstate->p_target_relation, NoLock);
	pstate->p_target_relation = NULL;
	pstate->p_target_rangetblentry = NULL;
}

/*
 * transformStmt -
 *	  transform a Parse tree into a Query tree.
 */
static Query *
transformStmt(ParseState *pstate, Node *parseTree,
			  List **extras_before, List **extras_after)
{
	Query	   *result = NULL;

	switch (nodeTag(parseTree))
	{
			/*
			 * Non-optimizable statements
			 */
		case T_CreateStmt:
			result = transformCreateStmt(pstate, (CreateStmt *) parseTree,
										 extras_before, extras_after);
			break;

		case T_IndexStmt:
			result = transformIndexStmt(pstate, (IndexStmt *) parseTree);
			break;

		case T_RuleStmt:
			result = transformRuleStmt(pstate, (RuleStmt *) parseTree,
									   extras_before, extras_after);
			break;

		case T_ViewStmt:
			result = transformViewStmt(pstate, (ViewStmt *) parseTree,
									   extras_before, extras_after);
			break;

		case T_ExplainStmt:
			{
				ExplainStmt *n = (ExplainStmt *) parseTree;

				result = makeNode(Query);
				result->commandType = CMD_UTILITY;
				n->query = transformStmt(pstate, (Node *) n->query,
										 extras_before, extras_after);
				result->utilityStmt = (Node *) parseTree;
			}
			break;

		case T_AlterTableStmt:
			result = transformAlterTableStmt(pstate,
											 (AlterTableStmt *) parseTree,
											 extras_before, extras_after);
			break;

		case T_PrepareStmt:
			result = transformPrepareStmt(pstate, (PrepareStmt *) parseTree);
			break;

		case T_ExecuteStmt:
			result = transformExecuteStmt(pstate, (ExecuteStmt *) parseTree);
			break;

			/*
			 * Optimizable statements
			 */
		case T_InsertStmt:
			result = transformInsertStmt(pstate, (InsertStmt *) parseTree,
										 extras_before, extras_after);
			break;

		case T_DeleteStmt:
			result = transformDeleteStmt(pstate, (DeleteStmt *) parseTree);
			break;

		case T_UpdateStmt:
			result = transformUpdateStmt(pstate, (UpdateStmt *) parseTree);
			break;

		case T_SelectStmt:
			if (((SelectStmt *) parseTree)->op == SETOP_NONE)
				result = transformSelectStmt(pstate,
											 (SelectStmt *) parseTree);
			else
				result = transformSetOperationStmt(pstate,
												   (SelectStmt *) parseTree);
			break;

		case T_DeclareCursorStmt:
			result = transformDeclareCursorStmt(pstate,
											(DeclareCursorStmt *) parseTree);
			break;

		default:

			/*
			 * other statements don't require any transformation-- just return
			 * the original parsetree, yea!
			 */
			result = makeNode(Query);
			result->commandType = CMD_UTILITY;
			result->utilityStmt = (Node *) parseTree;
			break;
	}

	/* Mark as original query until we learn differently */
	result->querySource = QSRC_ORIGINAL;
	result->canSetTag = true;

	/*
	 * Check that we did not produce too many resnos; at the very least we
	 * cannot allow more than 2^16, since that would exceed the range of a
	 * AttrNumber. It seems safest to use MaxTupleAttributeNumber.
	 */
	if (pstate->p_next_resno - 1 > MaxTupleAttributeNumber)
		ereport(ERROR,
				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
				 errmsg("target lists can have at most %d entries",
						MaxTupleAttributeNumber)));

	return result;
}

static Query *
transformViewStmt(ParseState *pstate, ViewStmt *stmt,
				  List **extras_before, List **extras_after)
{
	Query	   *result = makeNode(Query);

	result->commandType = CMD_UTILITY;
	result->utilityStmt = (Node *) stmt;

	stmt->query = transformStmt(pstate, (Node *) stmt->query,
								extras_before, extras_after);

	/*
	 * If a list of column names was given, run through and insert these into
	 * the actual query tree. - thomas 2000-03-08
	 *
	 * Outer loop is over targetlist to make it easier to skip junk targetlist
	 * entries.
	 */
	if (stmt->aliases != NIL)
	{
		ListCell   *alist_item = list_head(stmt->aliases);
		ListCell   *targetList;

		foreach(targetList, stmt->query->targetList)
		{
			TargetEntry *te = (TargetEntry *) lfirst(targetList);

			Assert(IsA(te, TargetEntry));
			/* junk columns don't get aliases */
			if (te->resjunk)
				continue;
			te->resname = pstrdup(strVal(lfirst(alist_item)));
			alist_item = lnext(alist_item);
			if (alist_item == NULL)
				break;			/* done assigning aliases */