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postgres/contrib/btree_gist/btree_utils_var.c
Heikki Linnakangas 670bf71f65 Remove dead NULL-pointer checks in GiST code. 
gist_poly_compress() and gist_circle_compress() checked for a NULL-pointer
key argument, but that was dead code; the gist code never passes a
NULL-pointer to the "compress" method.

This commit also removes a documentation note added in commit a0a3883,
about doing NULL-pointer checks in the "compress" method. It was added
based on the fact that some implementations were doing NULL-pointer
checks, but those checks were unnecessary in the first place.

The NULL-pointer check in gbt_var_same() function was also unnecessary.
The arguments to the "same" method come from the "compress", "union", or
"picksplit" methods, but none of them return a NULL pointer.

None of this is to be confused with SQL NULL values. Those are dealt with
by the gist machinery, and are never passed to the GiST opclass methods.

Michael Paquier
2015-01-28 10:03:58 +02:00

587 lines
13 KiB
C
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/*
* contrib/btree_gist/btree_utils_var.c
*/
#include "postgres.h"
#include "btree_gist.h"
#include <math.h>
#include <limits.h>
#include <float.h>
#include "btree_utils_var.h"
#include "utils/pg_locale.h"
#include "utils/builtins.h"
#include "utils/rel.h"
/* used for key sorting */
typedef struct
{
int i;
GBT_VARKEY *t;
} Vsrt;
typedef struct
{
const gbtree_vinfo *tinfo;
Oid collation;
} gbt_vsrt_arg;
PG_FUNCTION_INFO_V1(gbt_var_decompress);
Datum
gbt_var_decompress(PG_FUNCTION_ARGS)
{
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
GBT_VARKEY *key = (GBT_VARKEY *) DatumGetPointer(PG_DETOAST_DATUM(entry->key));
if (key != (GBT_VARKEY *) DatumGetPointer(entry->key))
{
GISTENTRY *retval = (GISTENTRY *) palloc(sizeof(GISTENTRY));
gistentryinit(*retval, PointerGetDatum(key),
entry->rel, entry->page,
entry->offset, FALSE);
PG_RETURN_POINTER(retval);
}
PG_RETURN_POINTER(entry);
}
/* Returns a better readable representaion of variable key ( sets pointer ) */
GBT_VARKEY_R
gbt_var_key_readable(const GBT_VARKEY *k)
{
GBT_VARKEY_R r;
r.lower = (bytea *) &(((char *) k)[VARHDRSZ]);
if (VARSIZE(k) > (VARHDRSZ + (VARSIZE(r.lower))))
r.upper = (bytea *) &(((char *) k)[VARHDRSZ + INTALIGN(VARSIZE(r.lower))]);
else
r.upper = r.lower;
return r;
}
GBT_VARKEY *
gbt_var_key_copy(const GBT_VARKEY_R *u, bool force_node)
{
GBT_VARKEY *r = NULL;
int32 lowersize = VARSIZE(u->lower);
int32 uppersize = VARSIZE(u->upper);
if (u->lower == u->upper && !force_node)
{ /* leaf key mode */
r = (GBT_VARKEY *) palloc(lowersize + VARHDRSZ);
memcpy(VARDATA(r), u->lower, lowersize);
SET_VARSIZE(r, lowersize + VARHDRSZ);
}
else
{ /* node key mode */
r = (GBT_VARKEY *) palloc0(INTALIGN(lowersize) + uppersize + VARHDRSZ);
memcpy(VARDATA(r), u->lower, lowersize);
memcpy(VARDATA(r) + INTALIGN(lowersize), u->upper, uppersize);
SET_VARSIZE(r, INTALIGN(lowersize) + uppersize + VARHDRSZ);
}
return r;
}
static GBT_VARKEY *
gbt_var_leaf2node(GBT_VARKEY *leaf, const gbtree_vinfo *tinfo)
{
GBT_VARKEY *out = leaf;
if (tinfo->f_l2n)
out = (*tinfo->f_l2n) (leaf);
return out;
}
/*
* returns the common prefix length of a node key
*/
static int32
gbt_var_node_cp_len(const GBT_VARKEY *node, const gbtree_vinfo *tinfo)
{
GBT_VARKEY_R r = gbt_var_key_readable(node);
int32 i = 0;
int32 l = 0;
int32 t1len = VARSIZE(r.lower) - VARHDRSZ;
int32 t2len = VARSIZE(r.upper) - VARHDRSZ;
int32 ml = Min(t1len, t2len);
char *p1 = VARDATA(r.lower);
char *p2 = VARDATA(r.upper);
if (ml == 0)
return 0;
while (i < ml)
{
if (tinfo->eml > 1 && l == 0)
{
if ((l = pg_mblen(p1)) != pg_mblen(p2))
{
return i;
}
}
if (*p1 != *p2)
{
if (tinfo->eml > 1)
{
return (i - l + 1);
}
else
{
return i;
}
}
p1++;
p2++;
l--;
i++;
}
return (ml); /* lower == upper */
}
/*
* returns true, if query matches prefix ( common prefix )
*/
static bool
gbt_bytea_pf_match(const bytea *pf, const bytea *query, const gbtree_vinfo *tinfo)
{
bool out = FALSE;
int32 qlen = VARSIZE(query) - VARHDRSZ;
int32 nlen = VARSIZE(pf) - VARHDRSZ;
if (nlen <= qlen)
{
char *q = VARDATA(query);
char *n = VARDATA(pf);
out = (memcmp(q, n, nlen) == 0);
}
return out;
}
/*
* returns true, if query matches node using common prefix
*/
static bool
gbt_var_node_pf_match(const GBT_VARKEY_R *node, const bytea *query, const gbtree_vinfo *tinfo)
{
return (tinfo->trnc && (
gbt_bytea_pf_match(node->lower, query, tinfo) ||
gbt_bytea_pf_match(node->upper, query, tinfo)
));
}
/*
* truncates / compresses the node key
* cpf_length .. common prefix length
*/
static GBT_VARKEY *
gbt_var_node_truncate(const GBT_VARKEY *node, int32 cpf_length, const gbtree_vinfo *tinfo)
{
GBT_VARKEY *out = NULL;
GBT_VARKEY_R r = gbt_var_key_readable(node);
int32 len1 = VARSIZE(r.lower) - VARHDRSZ;
int32 len2 = VARSIZE(r.upper) - VARHDRSZ;
int32 si;
char *out2;
len1 = Min(len1, (cpf_length + 1));
len2 = Min(len2, (cpf_length + 1));
si = 2 * VARHDRSZ + INTALIGN(len1 + VARHDRSZ) + len2;
out = (GBT_VARKEY *) palloc0(si);
SET_VARSIZE(out, si);
memcpy(VARDATA(out), r.lower, len1 + VARHDRSZ);
SET_VARSIZE(VARDATA(out), len1 + VARHDRSZ);
out2 = VARDATA(out) + INTALIGN(len1 + VARHDRSZ);
memcpy(out2, r.upper, len2 + VARHDRSZ);
SET_VARSIZE(out2, len2 + VARHDRSZ);
return out;
}
void
gbt_var_bin_union(Datum *u, GBT_VARKEY *e, Oid collation,
const gbtree_vinfo *tinfo)
{
GBT_VARKEY_R eo = gbt_var_key_readable(e);
GBT_VARKEY_R nr;
if (eo.lower == eo.upper) /* leaf */
{
GBT_VARKEY *tmp;
tmp = gbt_var_leaf2node(e, tinfo);
if (tmp != e)
eo = gbt_var_key_readable(tmp);
}
if (DatumGetPointer(*u))
{
GBT_VARKEY_R ro = gbt_var_key_readable((GBT_VARKEY *) DatumGetPointer(*u));
bool update = false;
nr.lower = ro.lower;
nr.upper = ro.upper;
if ((*tinfo->f_cmp) (ro.lower, eo.lower, collation) > 0)
{
nr.lower = eo.lower;
update = true;
}
if ((*tinfo->f_cmp) (ro.upper, eo.upper, collation) < 0)
{
nr.upper = eo.upper;
update = true;
}
if (update)
*u = PointerGetDatum(gbt_var_key_copy(&nr, TRUE));
}
else
{
nr.lower = eo.lower;
nr.upper = eo.upper;
*u = PointerGetDatum(gbt_var_key_copy(&nr, TRUE));
}
}
GISTENTRY *
gbt_var_compress(GISTENTRY *entry, const gbtree_vinfo *tinfo)
{
GISTENTRY *retval;
if (entry->leafkey)
{
GBT_VARKEY *r = NULL;
bytea *leaf = (bytea *) DatumGetPointer(PG_DETOAST_DATUM(entry->key));
GBT_VARKEY_R u;
u.lower = u.upper = leaf;
r = gbt_var_key_copy(&u, FALSE);
retval = palloc(sizeof(GISTENTRY));
gistentryinit(*retval, PointerGetDatum(r),
entry->rel, entry->page,
entry->offset, TRUE);
}
else
retval = entry;
return (retval);
}
GBT_VARKEY *
gbt_var_union(const GistEntryVector *entryvec, int32 *size, Oid collation,
const gbtree_vinfo *tinfo)
{
int i = 0,
numranges = entryvec->n;
GBT_VARKEY *cur;
Datum out;
GBT_VARKEY_R rk;
*size = sizeof(GBT_VARKEY);
cur = (GBT_VARKEY *) DatumGetPointer(entryvec->vector[0].key);
rk = gbt_var_key_readable(cur);
out = PointerGetDatum(gbt_var_key_copy(&rk, TRUE));
for (i = 1; i < numranges; i++)
{
cur = (GBT_VARKEY *) DatumGetPointer(entryvec->vector[i].key);
gbt_var_bin_union(&out, cur, collation, tinfo);
}
/* Truncate (=compress) key */
if (tinfo->trnc)
{
int32 plen;
GBT_VARKEY *trc = NULL;
plen = gbt_var_node_cp_len((GBT_VARKEY *) DatumGetPointer(out), tinfo);
trc = gbt_var_node_truncate((GBT_VARKEY *) DatumGetPointer(out), plen + 1, tinfo);
out = PointerGetDatum(trc);
}
return ((GBT_VARKEY *) DatumGetPointer(out));
}
bool
gbt_var_same(Datum d1, Datum d2, Oid collation,
const gbtree_vinfo *tinfo)
{
GBT_VARKEY *t1 = (GBT_VARKEY *) DatumGetPointer(d1);
GBT_VARKEY *t2 = (GBT_VARKEY *) DatumGetPointer(d2);
GBT_VARKEY_R r1,
r2;
r1 = gbt_var_key_readable(t1);
r2 = gbt_var_key_readable(t2);
return ((*tinfo->f_cmp) (r1.lower, r2.lower, collation) == 0 &&
(*tinfo->f_cmp) (r1.upper, r2.upper, collation) == 0);
}
float *
gbt_var_penalty(float *res, const GISTENTRY *o, const GISTENTRY *n,
Oid collation, const gbtree_vinfo *tinfo)
{
GBT_VARKEY *orge = (GBT_VARKEY *) DatumGetPointer(o->key);
GBT_VARKEY *newe = (GBT_VARKEY *) DatumGetPointer(n->key);
GBT_VARKEY_R ok,
nk;
*res = 0.0;
nk = gbt_var_key_readable(newe);
if (nk.lower == nk.upper) /* leaf */
{
GBT_VARKEY *tmp;
tmp = gbt_var_leaf2node(newe, tinfo);
if (tmp != newe)
nk = gbt_var_key_readable(tmp);
}
ok = gbt_var_key_readable(orge);
if ((VARSIZE(ok.lower) - VARHDRSZ) == 0 && (VARSIZE(ok.upper) - VARHDRSZ) == 0)
*res = 0.0;
else if (!(((*tinfo->f_cmp) (nk.lower, ok.lower, collation) >= 0 ||
gbt_bytea_pf_match(ok.lower, nk.lower, tinfo)) &&
((*tinfo->f_cmp) (nk.upper, ok.upper, collation) <= 0 ||
gbt_bytea_pf_match(ok.upper, nk.upper, tinfo))))
{
Datum d = PointerGetDatum(0);
double dres;
int32 ol,
ul;
gbt_var_bin_union(&d, orge, collation, tinfo);
ol = gbt_var_node_cp_len((GBT_VARKEY *) DatumGetPointer(d), tinfo);
gbt_var_bin_union(&d, newe, collation, tinfo);
ul = gbt_var_node_cp_len((GBT_VARKEY *) DatumGetPointer(d), tinfo);
if (ul < ol)
{
dres = (ol - ul); /* reduction of common prefix len */
}
else
{
GBT_VARKEY_R uk = gbt_var_key_readable((GBT_VARKEY *) DatumGetPointer(d));
unsigned char tmp[4];
tmp[0] = (unsigned char) (((VARSIZE(ok.lower) - VARHDRSZ) <= ul) ? 0 : (VARDATA(ok.lower)[ul]));
tmp[1] = (unsigned char) (((VARSIZE(uk.lower) - VARHDRSZ) <= ul) ? 0 : (VARDATA(uk.lower)[ul]));
tmp[2] = (unsigned char) (((VARSIZE(ok.upper) - VARHDRSZ) <= ul) ? 0 : (VARDATA(ok.upper)[ul]));
tmp[3] = (unsigned char) (((VARSIZE(uk.upper) - VARHDRSZ) <= ul) ? 0 : (VARDATA(uk.upper)[ul]));
dres = Abs(tmp[0] - tmp[1]) + Abs(tmp[3] - tmp[2]);
dres /= 256.0;
}
*res += FLT_MIN;
*res += (float) (dres / ((double) (ol + 1)));
*res *= (FLT_MAX / (o->rel->rd_att->natts + 1));
}
return res;
}
static int
gbt_vsrt_cmp(const void *a, const void *b, void *arg)
{
GBT_VARKEY_R ar = gbt_var_key_readable(((const Vsrt *) a)->t);
GBT_VARKEY_R br = gbt_var_key_readable(((const Vsrt *) b)->t);
const gbt_vsrt_arg *varg = (const gbt_vsrt_arg *) arg;
int res;
res = (*varg->tinfo->f_cmp) (ar.lower, br.lower, varg->collation);
if (res == 0)
return (*varg->tinfo->f_cmp) (ar.upper, br.upper, varg->collation);
return res;
}
GIST_SPLITVEC *
gbt_var_picksplit(const GistEntryVector *entryvec, GIST_SPLITVEC *v,
Oid collation, const gbtree_vinfo *tinfo)
{
OffsetNumber i,
maxoff = entryvec->n - 1;
Vsrt *arr;
int svcntr = 0,
nbytes;
char *cur;
GBT_VARKEY **sv = NULL;
gbt_vsrt_arg varg;
arr = (Vsrt *) palloc((maxoff + 1) * sizeof(Vsrt));
nbytes = (maxoff + 2) * sizeof(OffsetNumber);
v->spl_left = (OffsetNumber *) palloc(nbytes);
v->spl_right = (OffsetNumber *) palloc(nbytes);
v->spl_ldatum = PointerGetDatum(0);
v->spl_rdatum = PointerGetDatum(0);
v->spl_nleft = 0;
v->spl_nright = 0;
sv = palloc(sizeof(bytea *) * (maxoff + 1));
/* Sort entries */
for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
{
GBT_VARKEY_R ro;
cur = (char *) DatumGetPointer(entryvec->vector[i].key);
ro = gbt_var_key_readable((GBT_VARKEY *) cur);
if (ro.lower == ro.upper) /* leaf */
{
sv[svcntr] = gbt_var_leaf2node((GBT_VARKEY *) cur, tinfo);
arr[i].t = sv[svcntr];
if (sv[svcntr] != (GBT_VARKEY *) cur)
svcntr++;
}
else
arr[i].t = (GBT_VARKEY *) cur;
arr[i].i = i;
}
/* sort */
varg.tinfo = tinfo;
varg.collation = collation;
qsort_arg((void *) &arr[FirstOffsetNumber],
maxoff - FirstOffsetNumber + 1,
sizeof(Vsrt),
gbt_vsrt_cmp,
(void *) &varg);
/* We do simply create two parts */
for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
{
if (i <= (maxoff - FirstOffsetNumber + 1) / 2)
{
gbt_var_bin_union(&v->spl_ldatum, arr[i].t, collation, tinfo);
v->spl_left[v->spl_nleft] = arr[i].i;
v->spl_nleft++;
}
else
{
gbt_var_bin_union(&v->spl_rdatum, arr[i].t, collation, tinfo);
v->spl_right[v->spl_nright] = arr[i].i;
v->spl_nright++;
}
}
/* Truncate (=compress) key */
if (tinfo->trnc)
{
int32 ll = gbt_var_node_cp_len((GBT_VARKEY *) DatumGetPointer(v->spl_ldatum), tinfo);
int32 lr = gbt_var_node_cp_len((GBT_VARKEY *) DatumGetPointer(v->spl_rdatum), tinfo);
GBT_VARKEY *dl;
GBT_VARKEY *dr;
ll = Max(ll, lr);
ll++;
dl = gbt_var_node_truncate((GBT_VARKEY *) DatumGetPointer(v->spl_ldatum), ll, tinfo);
dr = gbt_var_node_truncate((GBT_VARKEY *) DatumGetPointer(v->spl_rdatum), ll, tinfo);
v->spl_ldatum = PointerGetDatum(dl);
v->spl_rdatum = PointerGetDatum(dr);
}
return v;
}
/*
* The GiST consistent method
*/
bool
gbt_var_consistent(GBT_VARKEY_R *key,
const void *query,
StrategyNumber strategy,
Oid collation,
bool is_leaf,
const gbtree_vinfo *tinfo)
{
bool retval = FALSE;
switch (strategy)
{
case BTLessEqualStrategyNumber:
if (is_leaf)
retval = (*tinfo->f_ge) (query, key->lower, collation);
else
retval = (*tinfo->f_cmp) (query, key->lower, collation) >= 0
|| gbt_var_node_pf_match(key, query, tinfo);
break;
case BTLessStrategyNumber:
if (is_leaf)
retval = (*tinfo->f_gt) (query, key->lower, collation);
else
retval = (*tinfo->f_cmp) (query, key->lower, collation) >= 0
|| gbt_var_node_pf_match(key, query, tinfo);
break;
case BTEqualStrategyNumber:
if (is_leaf)
retval = (*tinfo->f_eq) (query, key->lower, collation);
else
retval =
((*tinfo->f_cmp) (key->lower, query, collation) <= 0 &&
(*tinfo->f_cmp) (query, key->upper, collation) <= 0) ||
gbt_var_node_pf_match(key, query, tinfo);
break;
case BTGreaterStrategyNumber:
if (is_leaf)
retval = (*tinfo->f_lt) (query, key->upper, collation);
else
retval = (*tinfo->f_cmp) (query, key->upper, collation) <= 0
|| gbt_var_node_pf_match(key, query, tinfo);
break;
case BTGreaterEqualStrategyNumber:
if (is_leaf)
retval = (*tinfo->f_le) (query, key->upper, collation);
else
retval = (*tinfo->f_cmp) (query, key->upper, collation) <= 0
|| gbt_var_node_pf_match(key, query, tinfo);
break;
case BtreeGistNotEqualStrategyNumber:
retval = !((*tinfo->f_eq) (query, key->lower, collation) &&
(*tinfo->f_eq) (query, key->upper, collation));
break;
default:
retval = FALSE;
}
return retval;
}
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