/*
** STRATEGY
**
** Attempts to limit access scan to less than the entire De.ov_source
** relation by finding a key which can be used for associative
** access to the De.ov_source reln or an index thereon. The key is
** constructed from domain-value specifications found in the
** clauses of the qualification list using sub-routine findsimp
** in findsimp.c and other subroutines in file key.c
*/
int
strategy(void)
{
register int i, allexact;
acc_param_t sourceparm, indexparm;
index_t itup, rtup;
key_t lowikey[MAX_2ND_KEYS+1], highikey[MAX_2ND_KEYS+1];
key_t lowbkey[MAX_2ND_KEYS+1], highbkey[MAX_2ND_KEYS+1];
register desc_t *d;
extern desc_t Inddes;
char *tp;
long l_lid[MAXLID], h_lid[MAXLID];
int keytype;
long page, l, t;
int lidsize;
locator_t tidloc;
keytype = allexact = 0;
#ifdef xOTR1
if (tTf(70, 0))
printf("STRATEGY\tSource=%.12s\tNewq = %d\n",
De.ov_source ? De.ov_source->d_r.r_id : "(none)",
De.de_newq);
#endif
while (De.de_newq) /* if De.de_newq=TRUE then compute a new strategy */
/* NOTE: This while loop is executed only once */ {
De.ov_scanr = De.ov_source;
if (!De.ov_scanr)
return (1); /* return immediately if there is no source relation */
De.ov_fmode = NOKEY; /* assume a find mode with no key */
if (!De.ov_qlist)
break; /* if no qualification then you must scan entire rel */
/*
** Here we check for the special condition
** of a where clause consisting only of a tid.
*/
if (tid_only_test())
return(1);
/* copy structure of source relation into sourceparm */
paramd(De.ov_source, &sourceparm);
/* if source is unkeyed and has no sec index then give up */
if (sourceparm.mode == NOKEY && De.ov_source->d_r.r_indexed <= 0 && !De.ov_source->d_r.r_dim)
break;
/* find all simple clauses if any */
if (!findsimps())
break; /* break if there are no simple clauses */
/* Four steps are now performed to try and find a key.
** First if the relation is hashed then an exact key is search for
**
** Second if there are secondary indices, then a search is made
** for an exact key. If that fails then a check is made for
** a range key. The result of the rangekey check is saved.
**
** A step to check for possible use of Btrees is made here,
** although in actuality, an exact btreekey search is used
** after an exact range key search but before a range key search.
** A BTree range search is used only as a last alternative
** to a no key search.
**
** Third if the relation is an ISAM a check is made for
** an exact key or a range key.
**
** Fourth if there is a secondary index, then if step two
** found a key, that key is used.
**
** Lastly, give up and scan the entire relation
*/
/* step one. Try to find exact key on primary */
if (exactkey(&sourceparm, De.ov_lkey_struct)) {
De.ov_fmode = EXACTKEY;
break;
}
/* step two. If there is an index, try to find an exactkey on one of them */
if (De.ov_source->d_r.r_indexed > 0) {
opencatalog("indices", OR_READ);
ingres_setkey(&Inddes, &itup, De.ov_source->d_r.r_id, IRELIDP);
ingres_setkey(&Inddes, &itup, De.ov_source->d_r.r_owner, IOWNERP);
if ((i = find(&Inddes, EXACTKEY, &De.ov_lotid, &De.ov_hitid, (char *)&itup)) != 0)
syserr("strategy:find indices %d", i);
while (!(i = get(&Inddes, &De.ov_lotid, &De.ov_hitid, (char *)&itup, NXTTUP))) {
#ifdef xOTR1
if (tTf(70, 3))
printup(&Inddes, (char *)&itup);
#endif
if (!bequal(itup.i_relname, De.ov_source->d_r.r_id, MAX_NAME_SIZE) ||
!bequal(itup.i_owner, De.ov_source->d_r.r_owner, 2))
continue;
parami(&itup, &indexparm);
if (exactkey(&indexparm, De.ov_lkey_struct)) {
De.ov_fmode = EXACTKEY;
d = openindex(itup.i_index);
/* temp check for 6.0 index */
if ((int) d->d_r.r_indexed == -1)
ov_err(BADSECINDX);
De.ov_scanr = d;
break;
}
if (De.ov_fmode == LRANGEKEY)
continue; /* a range key on a s.i. has already been found */
if ((allexact = rangekey(&indexparm, lowikey, highikey)) != 0) {
bmove((char *)&itup, (char *)&rtup, sizeof(itup)); /* save tuple */
De.ov_fmode = LRANGEKEY;
}
}
if (i < 0)
syserr("stragery:bad get from index-rel %d", i);
/* If an exactkey on a secondary index was found, look no more. */
if (De.ov_fmode == EXACTKEY)
break;
}
/* attempt to use Btree in aiding search */
if ((i = btreekey(lowbkey, highbkey)) != 0) {
if (i > 0)
De.ov_fmode = BTREEKEY;
else if (De.ov_fmode != LRANGEKEY) {
/* use range key search over btree range search */
keytype = i;
De.ov_fmode = BTREERANGE;
}
}
/* step three. Look for a range key on primary */
if ((i = rangekey(&sourceparm, De.ov_lkey_struct, De.ov_hkey_struct)) != 0) {
if (i < 0)
De.ov_fmode = EXACTKEY;
else if (De.ov_fmode == BTREEKEY) {
/* use exact btree search over range search */
bmove((char *) lowbkey, (char *) De.ov_lkey_struct, sizeof(lowbkey));
bmove((char *) highbkey, (char *) De.ov_hkey_struct, sizeof(highbkey));
}
else
De.ov_fmode = LRANGEKEY;
break;
}
if (De.ov_fmode == BTREEKEY) {
bmove((char *) lowbkey, (char *) De.ov_lkey_struct, sizeof(lowbkey));
bmove((char *) highbkey, (char *) De.ov_hkey_struct, sizeof(highbkey));
break;
}
/* last step. If a secondary index range key was found, use it */
if (De.ov_fmode == LRANGEKEY) {
if (allexact < 0)
De.ov_fmode = EXACTKEY;
d = openindex(rtup.i_index);
/* temp check for 6.0 index */
if ((int) d->d_r.r_indexed == -1)
ov_err(BADSECINDX);
De.ov_scanr = d;
bmove((char *)lowikey, (char *)De.ov_lkey_struct, sizeof(lowikey));
bmove((char *)highikey, (char *)De.ov_hkey_struct, sizeof(highikey));
break;
}
/* nothing will work. give up! */
break;
}
/* check for De.de_newq = FALSE and no source relation */
if (!De.ov_scanr)
return (1);
/*
** At this point the strategy is determined.
**
** If De.ov_fmode is EXACTKEY then De.ov_lkey_struct contains
** the pointers to the keys.
**
** If De.ov_fmode is LRANGEKEY then De.ov_lkey_struct contains
** the pointers to the low keys and De.ov_hkey_struct
** contains pointers to the high keys.
**
** If De.ov_fmode is BTREEKEY then De.ov_lkey_struct contains
** pointers to the key lid.
**
** If De.ov_fmode is BTREERANGE then lowbkey contains pointers
** to the low key lid and highbkey contains pointers to the
** high key lid.
**
** If De.ov_fmode is NOKEY, then a full scan will be performed
*/
#ifdef xOTR1
if (tTf(70, -1))
printf("De.ov_fmode= %d\n",De.ov_fmode);
#endif
if (De.ov_fmode == BTREERANGE) {
/* requires special type of search to limit tid scan */
for (i = 0; i < De.ov_scanr->d_r.r_dim; ++i) {
l_lid[i] = 0;
h_lid[i] = 0;
}
lidsize = LIDSIZE * De.ov_scanr->d_r.r_dim;
/* get low lids */
if (keytype == -1 || keytype == -3) {
tp = De.ov_keyl + De.ov_scanr->d_r.r_width - lidsize;
bmove(l_lid, tp, lidsize);
setallkey(lowbkey, De.ov_keyl);
bmove(tp, l_lid, lidsize);
}
/* get high lids */
if (keytype == -2 || keytype == -3) {
tp = De.ov_keyh + De.ov_scanr->d_r.r_width - lidsize;
bmove(h_lid, tp, lidsize);
setallkey(highbkey, De.ov_keyh);
bmove(tp, h_lid, lidsize);
}
setglobalint(BTREE_FD_NAME, De.ov_scanr->d_btreefd);
/* scan through lids to fill in unprovided lids and to check
** for lids that are too big
*/
page = RT;
for (i = 0; i < De.ov_scanr->d_r.r_dim; ++i) {
if (l_lid[i] <= 0)
l_lid[i] = 1;
l = last_lid(page) - 1;
if (h_lid[i] < 0)
return(0);
if (!h_lid[i] || h_lid[i] > l)
h_lid[i] = l;
if ((t = get_tid(page, h_lid[i], &tidloc)) < 0)
syserr("bad gettid in strategy, lid = %ld\n", h_lid[i]);
page = t;
}
/* check whether lo > hi */
for (i = 0; i < De.ov_scanr->d_r.r_dim; ++i)
if (l_lid[i] < h_lid[i])
break;
else if (l_lid[i] > h_lid[i])
return(0);
#ifdef xOTR1
if (tTf(70,0))
for (i = 0 ; i < De.ov_scanr->d_r.r_dim; ++i)
printf("hi = %ld, lo = %ld\n", h_lid[i], l_lid[i]);
#endif
/* find the smallest and largest possible tids of the lids
** within the provided range */
btreerange(De.ov_scanr, l_lid, h_lid, &De.ov_lotid, &De.ov_hitid);
} else {
/* set up the key tuples */
if (De.ov_fmode != NOKEY) {
if (setallkey(De.ov_lkey_struct, De.ov_keyl))
return (0); /* query false. There is a simple
** clause which can never be satisfied.
** These simple clauses can be choosey!
*/
}
if ((i = find(De.ov_scanr, De.ov_fmode, &De.ov_lotid, &De.ov_hitid, De.ov_keyl)) != 0)
syserr("strategy:find1 %.12s, %d", De.ov_scanr->d_r.r_id, i);
if (De.ov_fmode == LRANGEKEY) {
setallkey(De.ov_hkey_struct, De.ov_keyh);
if ((i = find(De.ov_scanr, HRANGEKEY, &De.ov_lotid, &De.ov_hitid, De.ov_keyh)) != 0)
syserr("strategy:find2 %.12s, %d", De.ov_scanr->d_r.r_id, i);
}
}
#ifdef xOTR1
if (tTf(70, 1)) {
printf("Lo");
dumptid(&De.ov_lotid);
printf("Hi");
dumptid(&De.ov_hitid);
}
#endif
return (1);
}
strategy()
{
register int i, allexact;
struct accessparam sourceparam, indexparam;
struct index itup, rtup;
struct key lowikey[MAXKEYS+1], highikey[MAXKEYS+1];
register struct descriptor *d;
extern struct descriptor Inddes;
struct descriptor *openindex();
# ifdef xOTR1
if (tTf(31, 0))
printf("STRATEGY\tSource=%.12s\tNewq = %d\n", Source ? Source->relid : "(none)", Newq);
# endif
while (Newq) /* if Newq=TRUE then compute a new strategy */
/* NOTE: This while loop is executed only once */
{
Scanr = Source;
if (!Scanr)
return (1); /* return immediately if there is no source relation */
Fmode = NOKEY; /* assume a find mode with no key */
if (!Qlist)
break; /* if no qualification then you must scan entire rel */
/* copy structure of source relation into sourceparam */
paramd(Source, &sourceparam);
/* if source is unkeyed and has no sec index then give up */
if (sourceparam.mode == NOKEY && Source->relindxd <= 0)
break;
/* find all simple clauses if any */
if (!findsimps())
break; /* break if there are no simple clauses */
/* Four steps are now performed to try and find a key.
** First if the relation is hashed then an exact key is search for
**
** Second if there are secondary indexes, then a search is made
** for an exact key. If that fails then a check is made for
** a range key. The result of the rangekey check is saved.
**
** Third if the relation is an ISAM a check is made for
** an exact key or a range key.
**
** Fourth if there is a secondary index, then if step two
** found a key, that key is used.
**
** Lastly, give up and scan the entire relation
*/
/* step one. Try to find exact key on primary */
if (exactkey(&sourceparam, &Lkey_struct))
{
Fmode = EXACTKEY;
break;
}
/* step two. If there is an index, try to find an exactkey on one of them */
if (Source->relindxd)
{
opencatalog("indexes", 0);
setkey(&Inddes, &itup, Source->relid, IRELIDP);
setkey(&Inddes, &itup, Source->relowner, IOWNERP);
if (i = find(&Inddes, EXACTKEY, &Lotid, &Hitid, &itup))
syserr("strategy:find indexes %d", i);
while (!(i = get(&Inddes, &Lotid, &Hitid, &itup, NXTTUP)))
{
# ifdef xOTR1
if (tTf(31, 3))
printup(&Inddes, &itup);
# endif
if (!bequal(itup.irelidp, Source->relid, MAXNAME) ||
!bequal(itup.iownerp, Source->relowner, 2))
continue;
parami(&itup, &indexparam);
if (exactkey(&indexparam, &Lkey_struct))
{
Fmode = EXACTKEY;
d = openindex(itup.irelidi);
/* temp check for 6.0 index */
if (d->relindxd == -1)
ov_err(BADSECINDX);
Scanr = d;
break;
}
if (Fmode == LRANGEKEY)
continue; /* a range key on a s.i. has already been found */
if (allexact = rangekey(&indexparam, &lowikey, &highikey))
{
bmove(&itup, &rtup, sizeof itup); /* save tuple */
Fmode = LRANGEKEY;
}
}
if (i < 0)
syserr("stragery:bad get from index-rel %d", i);
/* If an exactkey on a secondary index was found, look no more. */
if (Fmode == EXACTKEY)
break;
}
/* step three. Look for a range key on primary */
if (i = rangekey(&sourceparam, &Lkey_struct, &Hkey_struct))
{
if (i < 0)
Fmode = EXACTKEY;
else
Fmode = LRANGEKEY;
break;
}
/* last step. If a secondary index range key was found, use it */
if (Fmode == LRANGEKEY)
{
if (allexact < 0)
Fmode = EXACTKEY;
d = openindex(rtup.irelidi);
/* temp check for 6.0 index */
if (d->relindxd == -1)
ov_err(BADSECINDX);
Scanr = d;
bmove(&lowikey, &Lkey_struct, sizeof lowikey);
bmove(&highikey, &Hkey_struct, sizeof highikey);
break;
}
/* nothing will work. give up! */
break;
}
/* check for Newq = FALSE and no source relation */
if (!Scanr)
return (1);
/*
** At this point the strategy is determined.
**
** If Fmode is EXACTKEY then Lkey_struct contains
** the pointers to the keys.
**
** If Fmode is LRANGEKEY then Lkey_struct contains
** the pointers to the low keys and Hkey_struct
** contains pointers to the high keys.
**
** If Fmode is NOKEY, then a full scan will be performed
*/
# ifdef xOTR1
if (tTf(31, -1))
printf("Fmode= %d\n",Fmode);
# endif
/* set up the key tuples */
if (Fmode != NOKEY)
{
if (setallkey(&Lkey_struct, Keyl))
return (0); /* query false. There is a simple
** clause which can never be satisfied.
** These simple clauses can be choosey!
*/
}
if (i = find(Scanr, Fmode, &Lotid, &Hitid, Keyl))
syserr("strategy:find1 %.12s, %d", Scanr->relid, i);
if (Fmode == LRANGEKEY)
{
setallkey(&Hkey_struct, Keyh);
if (i = find(Scanr, HRANGEKEY, &Lotid, &Hitid, Keyh))
syserr("strategy:find2 %.12s, %d", Scanr->relid, i);
}
# ifdef xOTR1
if (tTf(31, 1))
{
printf("Lo");
dumptid(&Lotid);
printf("Hi");
dumptid(&Hitid);
}
# endif
return (1);
}
