2.11BSD/ingres/source/decomp/exec_sq.c

# include	"../pipes.h"
# include	"../ingres.h"
# include	"../tree.h"
# include	"../symbol.h"
# include	"decomp.h"

/*
** DECOMP2 -- Routines for executing detached sub-queries appearing
**	in sqlist. These routines include:
**
**	exec_sq -- execute sub-queries and update range table.
**
**	undo_sq -- restore range table and destroy temp rels.
**
**	reset_sq - restore range table and reset temp rels.
**
**	execsq1 -- call ovqp with subquery.
*/


exec_sq(sqlist, sqrange, disj)
struct querytree	*sqlist[];
int			sqrange[];
int			*disj;

/*
** Exec_sq -- execute the subqueries in sqlist. Associated with
**	each sub-query is a relation number stored in sqrange.
**	If the sub-query has a non-null target list, the range
**	table is updated to reflect the new range of the relation.
**
**	If any sub-query is false, all subsequent ones are ignored
**	by ovqp and exec_sq returns the var number of the false subquery.
**
**	As a side effect, "disj" is incremented for each disjoint sub-query
*/

{
	register struct querytree	*sq;
	register int			i, qualfound;

#	ifdef xDTR1
	if (tTf(11, 0))
		printf("EXEC_SQ--\n");
#	endif

	*disj = 0;

	for (i = 0; i < MAXRANGE; i++)
	{
		if (sq = sqlist[i])
		{
#			ifdef xDTR1
			if (tTf(11, 1))
				printf("sq[%d]=%l\n", i, sq);
#			endif
			qualfound = execsq1(sq, i, sqrange[i]);

#			ifdef xDTR1
			if (tTf(11, 2))
				printf("qualfound=%d\n", qualfound);
#			endif
			if (!qualfound)
			{
				return(i);
			}
			if (sq->left->sym.type != TREE)
			{
				/*
				** Update the range table and open
				** the relation's restricted replacement.
				*/
				new_range(i, sqrange[i]);
				openr1(i);
			}
			else
			{
				(*disj)++;
			}
		}
	}
	return (-1);
}


undo_sq(sqlist, locrang, sqrange, limit, maxlimit, reopen)
char		*sqlist[];
int		locrang[];
int		sqrange[];
int		limit;
int		maxlimit;
int		reopen;

/*
**	Undo the effects of one variable detachment on
**	the range table. The two parameters "limit" and
**	"maxlimit" describe how far down the list of
**	subqueries were processed.  Maxlimit represents
**	the furthest every attained and limit represents
**	the last variable processed the last time.
*/

{

	register struct querytree	*sq;
	register int			i, lim;

#	ifdef xDTR1
	if (tTf(11, 0))
		printf("UNDO_SQ--\n");
#	endif


	initp();	/* setup parm vector for destroys */
	lim = limit == -1 ? MAXRANGE : limit;
	if (maxlimit == -1)
		maxlimit = MAXRANGE;

	for (i = 0; i < MAXRANGE; i++)
		if (sq = (struct querytree *) sqlist[i])
		{
			if (sq->left->sym.type != TREE)
			{
				if (i < lim)
				{
					/* The query was run. Close the temp rel */
					closer1(i);
				}

				/* mark the temporary to be destroyed */
				dstr_mark(sqrange[i]);

				/* reopen the original relation. If maxlimit
				** never reached the variable "i" then the
				** original relation was never closed and thus
				** doesn't need to be reopened.
				*/
				rstrang(locrang, i);
				if (reopen && i < maxlimit)
					openr1(i);
			}
		}
	dstr_flush(0);	/* call destroy */
}


execsq1(sq, var, relnum)
struct querytree 	*sq;
int			var;
int			relnum;

/*
** Execsq1 -- call ovqp with mdRETR on temp relation
*/

{
	register int	qualfound;

	Sourcevar = var;
	Newq = 1;
	qualfound = call_ovqp(sq, mdRETR, relnum);
	return (qualfound);
}


reset_sq(sqlist, locrang, limit)
struct querytree	*sqlist[];
int			locrang[];
int			limit;

/*
**	Reset each relation until limit.
**	Reset will remove all tuples from the
**	relation but not destroy the relation.
**	The descriptor for the relation will be removed
**	from the cache.
**
**	The original relation is returned to
**	the range table.
**
**	If limit is -1 then all relations are done.
*/

{
	register struct querytree	*sq;
	register int			i, lim;
	int				old, reset;

	lim = limit == -1 ? MAXRANGE : limit;
	reset = FALSE;
	initp();

	for (i = 0; i < lim; i++)
		if ((sq = sqlist[i]) && sq->left->sym.type != TREE)
		{
			old = new_range(i, locrang[i]);
			setp(rnum_convert(old));
			specclose(old);
			reset = TRUE;
		}

	if (reset)
	{
		/*
		** Guarantee that OVQP will not reuse old
		** page of relation being reset
		*/
		Newr = TRUE;
		call_dbu(mdRESETREL, FALSE);
	}
}