2.11BSD/ingres/source/decomp/aggregate.c
# include "../ingres.h"
# include "../tree.h"
# include "../symbol.h"
# include "decomp.h"
struct agglist
{
struct querytree **father; /* addr of pointer to you */
struct querytree *agpoint; /* pointer to aghead */
struct querytree *agfather; /* is your father an aggregate? */
int agvarno; /* var # assigned to aggr fnct */
};
struct hitlist
{
struct querytree **trepr; /* position in tree to be changed */
int byno; /* by-list position */
};
struct agglist *Aggnext;
aggregate(root)
struct querytree *root;
/*
** AGGREGATE - replace aggregates with their values
**
** Aggregate attempts to optimize aggregate processing
** wherever possible. It replaces aggregates with their
** values, and links aggregate functions which have
** identical by-lists together.
**
** Note that for the sake of this code, A "prime"
** aggregate is one in which duplicates are removed.
** These are COUNTU, SUMU, and AVGU.
**
** Aggregate first forms a list of all aggregates in
** the order they should be processed.
**
** For each aggregate, it looks at all other aggregates
** to see if there are two simple aggregates
** or if there is another aggregate funtion with the
** same by-list.
**
** An attempt is made to run
** as many aggregates as possible at once. This can be
** done only if two or more aggregates have the same
** qualifications and in the case of aggregate functions,
** they must have identical by-lists.
** Even then, certain combinations
** of aggregates cannot occure together. The list is
** itemized later in the code.
**
** Aggregate calls BYEVAL or AGEVAL to actually process
** aggregate functions or aggregates respectively.
**
*/
{
struct agglist alist[MAXAGG + 1];
struct querytree *rlist[MAXAGG + 1];
struct agglist *al, *al1;
register struct querytree *agg, *aop1, *r;
struct querytree *aop, *agg1;
int i, simple_agg, varmap;
int attcnt, anyagg, attoff, twidth;
struct querytree *makavar(), *agspace();
al = alist;
Aggnext = al;
findagg(&root, root); /* generate list of all aggregates */
Aggnext->agpoint = 0; /* mark end of the list */
anyagg = 0;
varmap = ((struct qt_root *)root)->lvarm | ((struct qt_root *)root)->rvarm;
/* process each aggregate */
for (;agg = al->agpoint; al++)
{
/* is this still an aggregate? */
if (agg->sym.type != AGHEAD)
continue;
mapvar(agg, 0); /* map the aggregate tree */
anyagg++;
Sourcevar = bitpos(((struct qt_root *)agg)->lvarm | ((struct qt_root *)agg)->rvarm);
# ifdef xDTR1
if (tTf(6, 4))
printf("Sourcevar=%d,rel=%s\n", Sourcevar, rangename(Sourcevar));
# endif
simple_agg = (agg->left->sym.type == AOP); /* TRUE if no bylist */
aop = agg->left; /* assume it was TRUE */
# ifdef xDTR1
if (tTf(6, 0))
printf("%s\n", simple_agg ? "agg" : "agg-func");
# endif
if (simple_agg)
{
/* simple aggregate */
rlist[0] = agspace(aop);
twidth = ((struct qt_var *)aop)->frml & I1MASK; /* init width to the width of the aggregate */
}
else
{
attoff = ((struct qt_res *)agg->left->left)->resno + 2;
aop = aop->right; /* find the AOP node */
/* assign new source variable for aggregate */
al->agvarno = getrange(&varmap);
/* compute width of bylist + count field */
twidth = findwid(agg->left) + 4;
/* make sure the aggregate does not exceed max dimensions */
if (chkwidth(aop, &twidth, attoff))
derror(AGFTOBIG);
}
attcnt = 1; /* one aggregate so far */
/* look for another identical aggregate */
for (al1 = al + 1; agg1 = al1->agpoint; al1++)
{
/* if agg is nested inside agg1 then ignore it */
if (al->agfather == agg1 || agg1->sym.type != AGHEAD)
continue;
/* split aggs and agg-func apart */
/* check for identical aggregate */
if (simple_agg)
{
aop1 = agg1->left; /* find AOP node */
if (aop1->sym.type != AOP)
continue; /* not a simple agg */
/* make sure they can be run together */
if (checkagg(agg, aop, agg1, aop1) == 0)
continue;
if ((i = sameagg(agg, aop1, attcnt)) >= 0)
{
/* found identical aggregate to rlist[i] */
r = rlist[i];
}
else
{
/* put this agg in with the others */
/* first make sure it won't exceed tuple length */
if (chkwidth(aop1, &twidth, 0))
continue; /* can't be included */
r = rlist[attcnt++] = agspace(aop1);
/* connect into tree */
aop1->left = agg->left;
agg->left = aop1;
}
}
else
{
/* aggregate function */
if (!sameafcn(agg->left->left, agg1->left->left))
continue;
aop1 = agg1->left->right; /* find AOP */
if (checkagg(agg, aop, agg1, aop1) == 0)
{
/* same by-lists but they can't be run together */
continue;
}
if ((i = sameagg(agg, aop1, attcnt)) < 0)
{
/* make sure there is room */
if (chkwidth(aop1, &twidth, attcnt + attoff))
continue;
/* add aggregate into tree */
i = attcnt++;
aop1->left = agg->left->right;
agg->left->right = aop1;
}
r = makavar(aop1, al->agvarno, i + attoff);
}
/* replace aggregate in original tree with its value */
*(al1->father) = r;
/* remove aggregate from local list */
agg1->sym.type = -1;
# ifdef xDTR1
if (tTf(6, 3))
printf("including aghead %l\n", agg1);
# endif
}
/* process aggregate */
if (simple_agg)
{
rlist[attcnt] = 0;
ageval(agg, rlist); /* pass tree and result list */
r = rlist[0];
}
else
{
opt_bylist(&alist, agg);
byeval(al->agfather, agg, al->agvarno);
r = makavar(aop, al->agvarno, attoff);
}
/*
** Link result into tree. al->father hold the address
** &(tree->left) or &(tree->right).
*/
*(al->father) = r;
# ifdef xDTR1
if (tTf(6, 4))
printree(*(al->father), "aggregate value");
# endif
}
if (anyagg)
{
opt_bylist(&alist, root);
mapvar(root, 0); /* remap main tree */
}
}
findagg(nodep, agf)
struct querytree **nodep;
struct querytree *agf;
/*
** findagg builds a list of all aggregates
** in the tree. It finds them by leftmost
** innermost first.
**
** The parameters represent:
** nodep: the address of the node pointing to you
** eg. &(tree->left) or &(tree->right)
** agf: the root node. or if we are inside
** a nested aggregate, the AGHEAD node
*/
{
register struct querytree *q, *f;
register struct agglist *list;
int agg;
if ((q = *nodep) == NULL)
return;
f = agf;
if (agg = (q->sym.type == AGHEAD))
f = q; /* this aggregate is now the father root */
/* find all aggregates below */
findagg(&(q->left), f);
findagg(&(q->right), f);
/* if this is an aggregate, put it on the list */
if (agg)
{
list = Aggnext;
list->father = nodep;
list->agpoint = q;
list->agfather = agf;
Aggnext++;
}
}
struct querytree *agspace(aop)
struct querytree *aop;
/*
** Agspace allocates space for the result of
** a simple aggregate.
*/
{
register struct querytree *a, *r;
register int length;
struct querytree *need();
a = aop;
length = ((struct qt_var *)a)->frml & I1MASK;
r = need(Qbuf, length + 6);
r->left = r->right = 0;
r->sym.type = ((struct qt_var *)a)->frmt;
r->sym.len = length;
return (r);
}
chkwidth(aop, widthp, domno)
struct querytree *aop;
int *widthp;
int domno;
/*
** Chkwidth -- make sure that the inclusion of another aggregate will
** not exceed the system limit. This means that the total width
** cannot exceed MAXTUP and the number of domains cannot exceed MAXDOM-1
*/
{
register int width;
width = *widthp;
# ifdef xDTR1
if (tTf(6, 10))
printf("agg width %d,dom %d\n", width, domno);
# endif
width += (((struct qt_var *)aop)->frml & I1MASK);
if (width > MAXTUP || domno > MAXDOM - 1)
return (1);
*widthp = width;
return (0);
}
cprime(aop)
struct querytree *aop;
/*
** Determine whether an aggregate is prime
** or a don't care aggregate. Returns TRUE
** if COUNTU,SUMU,AVGU,MIN,MAX,ANY.
** Returns false if COUNT,SUM,AVG.
*/
{
register int i;
i = TRUE;
switch (aop->sym.value[0])
{
case opCOUNT:
case opSUM:
case opAVG:
i = FALSE;
}
return (i);
}
getrange(varmap)
int *varmap;
/*
** Getrange find a free slot in the range table
** for an aggregate function.
**
** If there are no free slots,derror is called
*/
{
register int i, map, bit;
map = *varmap;
for (i = 0; i < MAXRANGE; i++)
{
/* if slot is used, continue */
if ((bit = 1 << i) & map)
continue;
map |= bit; /* "or" bit into the map */
*varmap = map;
# ifdef xDTR1
if (tTf(6, 10))
printf("Assn var %d, map %o\n", i, map);
# endif
return (i);
}
derror(NODESCAG);
}
checkagg(aghead1, aop1, aghead2, aop2)
struct querytree *aghead1;
struct querytree *aop1;
struct querytree *aghead2;
struct querytree *aop2;
{
register struct querytree *aop_1, *aop_2, *agg1;
int ok;
/* two aggregate functions can be run together
** according to the following table:
**
** prime !prime don't care
**
** prime afcn? never afcn?
** !prime never always always
** don't care afcn? always always
**
** don't care includes: ANY, MIN, MAX
** afcn? means only if a-fcn's are identical
*/
aop_1 = aop1;
aop_2 = aop2;
agg1 = aghead1;
if (!prime(aop_1) && !prime(aop_2))
ok = TRUE;
else
if (sameafcn(aop_1->right, aop_2->right))
ok = cprime(aop_1) && cprime(aop_2);
else
ok = FALSE;
/* The two aggregates must range over the same variables */
if ((((struct qt_root *)agg1)->lvarm | ((struct qt_root *)agg1)->rvarm)
!= (((struct qt_root *)aghead2)->lvarm | ((struct qt_root *)aghead2)->rvarm))
ok = FALSE;
/* check the qualifications */
if (ok)
ok = sameafcn(agg1->right, aghead2->right);
return (ok);
}
sameagg(aghead, newaop, agg_depth)
struct querytree *aghead;
struct querytree *newaop;
int agg_depth;
{
register struct querytree *agg, *newa;
register int i;
agg = aghead;
newa = newaop;
agg = agg->left;
if (agg->sym.type == BYHEAD)
agg = agg->right;
/* agg now points to first aggregate */
for (i = 1; agg; agg = agg->left, i++)
if (sameafcn(agg->right, newa->right) && agg->sym.value[0] == newa->sym.value[0])
{
# ifdef xDTR1
if (tTf(6, 6))
printf("found identical aop %l\n", newa);
# endif
return (agg_depth - i);
}
/* no match */
return (-1);
}
struct hitlist *Hnext, *Hlimit;
opt_bylist(alist, root)
struct agglist *alist;
struct querytree *root;
{
register struct agglist *al;
register struct querytree *agg;
register struct hitlist *hl;
struct querytree **tpr, *tree, *lnodv[MAXDOM+2];
struct hitlist hlist[30];
int anyop, i, usedmap, vars, treemap;
extern struct querytree *makavar();
/* compute bitmap of all possible vars in tree (can include xtra vars) */
treemap = ((struct qt_root *)root)->lvarm | ((struct qt_root *)root)->rvarm;
anyop = FALSE;
/* scan the list of aggregates looking for one nested in root */
for (al = alist; (agg = al->agpoint) && agg != root; al++)
{
if (agg->sym.type == AGHEAD && agg->left->sym.type == BYHEAD &&
al->agfather == root)
{
/* this aggregate function is nested in root */
/* make sure it has some vars of interest */
if ((treemap & varfind(agg->left->left, NULL)) == 0)
continue;
# ifdef xDTR1
if (tTf(6, 11))
printree(agg, "nested agg");
# endif
/* form list of bydomains */
lnodv[lnode(agg->left->left, lnodv, 0)] = 0;
usedmap = 0;
Hnext = &hlist[0];
Hlimit = &hlist[30];
/* find all possible replacements */
vars = modtree(&root, lnodv, &usedmap);
/*
** All references to a variable must be replaced
** in order to use this aggregates by-domains.
*/
if (usedmap && ((vars & usedmap) == 0))
{
# ifdef xDTR1
if (tTf(6, 7))
printf("Committed\n");
# endif
/* success. Committ the tree changes */
Hnext->trepr = NULL;
for (hl = &hlist[0]; tpr = hl->trepr; hl++)
{
/* get bydomain number */
i = hl->byno;
/* get node being replaced */
tree = *tpr;
/* if it is already a var, just change it */
if (tree->sym.type == VAR)
{
((struct qt_var *)tree)->varno = al->agvarno;
((struct qt_var *)tree)->attno = i + 2;
}
else
*tpr = makavar(lnodv[i], al->agvarno, i + 2);
anyop = TRUE;
# ifdef xDTR1
if (tTf(6, 7))
printree(*tpr, "modified tree");
# endif
}
}
/* vars is now a map of the variables in the root */
treemap = vars;
}
}
/* if any changes were made, get rid of the unnecessary links */
if (anyop)
chklink(root);
}
modtree(pnode, lnodv, replmap)
struct querytree **pnode;
struct querytree *lnodv[];
int *replmap;
{
register struct querytree *tree;
register int vars, i;
struct querytree *afcn;
/* point up current node */
if ((tree = *pnode) == NULL)
return (0);
/* examine each by-list for match on this subtree */
for (i = 0; afcn = lnodv[i]; i++)
{
if (sameafcn(tree, afcn->right))
{
# ifdef xDTR1
if (tTf(6, 9))
printree(tree, "potential Jackpot");
# endif
vars = varfind(tree, NULL);
if (Hnext == Hlimit)
return (vars); /* no more room */
/* record what needs to be done */
Hnext->trepr = pnode;
Hnext->byno = i;
Hnext++;
*replmap |= vars;
return (0);
}
}
if (tree->sym.type == VAR)
return (01 << ((struct qt_var *)tree)->varno);
/* try the subtrees */
vars = modtree(&(tree->left), lnodv, replmap);
if ((vars & *replmap) == 0)
vars |= modtree(&(tree->right), lnodv, replmap);
return (vars);
}
chklink(root)
struct querytree *root;
{
register struct querytree *r, *b, *last;
last = root;
for (r = last->right; r->sym.type != QLEND; r = r->right)
{
/* if this is an EQ node then check for an unnecessary compare */
if ((b = r->left)->sym.type == BOP && ((struct qt_op *)b)->opno == opEQ)
{
if (sameafcn(b->left, b->right))
{
# ifdef xDTR1
if (tTf(6, 5))
printree(b, "unnec clause");
# endif
last->right = r->right;
continue;
}
}
last = r;
}
}
sameafcn(q1, q2)
struct querytree *q1, *q2;
{
register struct querytree *t1, *t2;
register int len;
int type;
t1 = q1;
t2 = q2;
if (!(t1 && t2))
return(!(t1 || t2));
len = (t1->sym.len & 0377) + 2;
type = t1->sym.type;
if (type == VAR)
len = 6;
if (type == AND)
len = 2;
if (!bequal(&t1->sym, &t2->sym, len))
return(0);
return(sameafcn(t1->left,t2->left) && sameafcn(t1->right,t2->right));
}
varfind(root, aghead)
struct querytree *root;
struct querytree *aghead;
/*
** varfind -- find all variables in the tree pointed to by "root".
** Examine all parts of the tree except aggregates. For
** aggregates, ignore simple aggregate and look only
** at the by-lists of aggregate functions. If the aggregate
** is "aghead" then ignore it. There is no reason to look
** at yourself!!!!
** This routine is called by byeval() to determine
** whether to link the aggregate to the root tree.
**
** Curiosity note: since the tree being examined has not been
** processed by decomp yet, ckvar does not need to be called
** since the var could not have been altered.
*/
{
register struct querytree *tree;
register int type;
if ((tree = root) == NULL)
return (0);
if ((type = tree->sym.type) == AGHEAD)
{
/* ignore if it matches aghead */
if (tree == aghead)
return (0);
/* if this is an aggregate function, look at bylist */
tree = tree->left;
if ((type = tree->sym.type) != BYHEAD)
return (0);
}
if (type == VAR)
return (1 << ((struct qt_var *)tree)->varno);
return (varfind(tree->left, aghead) | varfind(tree->right, aghead));
}