postgresql/contrib/intarray/_int_gist.c
Tom Lane 9034a2d512 Fix integer-overflow problem in intarray's g_int_decompress().
An array element equal to INT_MAX gave this code indigestion,
causing an infinite loop that surely ended in SIGSEGV.  We fixed
some nearby problems awhile ago (cf 757c5182f) but missed this.

Report and diagnosis by Alexander Lakhin (bug #18273); patch by me

Discussion: https://postgr.es/m/18273-9a832d1da122600c@postgresql.org
2024-01-07 15:19:50 -05:00

638 lines
15 KiB
C

/*
* contrib/intarray/_int_gist.c
*/
#include "postgres.h"
#include <limits.h>
#include <math.h>
#include "_int.h"
#include "access/gist.h"
#include "access/reloptions.h"
#include "access/stratnum.h"
#define GETENTRY(vec,pos) ((ArrayType *) DatumGetPointer((vec)->vector[(pos)].key))
/*
* Control the maximum sparseness of compressed keys.
*
* The upper safe bound for this limit is half the maximum allocatable array
* size. A lower bound would give more guarantees that pathological data
* wouldn't eat excessive CPU and memory, but at the expense of breaking
* possibly working (after a fashion) indexes.
*/
#define MAXNUMELTS (Min((MaxAllocSize / sizeof(Datum)),((MaxAllocSize - ARR_OVERHEAD_NONULLS(1)) / sizeof(int)))/2)
/* or: #define MAXNUMELTS 1000000 */
/*
** GiST support methods
*/
PG_FUNCTION_INFO_V1(g_int_consistent);
PG_FUNCTION_INFO_V1(g_int_compress);
PG_FUNCTION_INFO_V1(g_int_decompress);
PG_FUNCTION_INFO_V1(g_int_penalty);
PG_FUNCTION_INFO_V1(g_int_picksplit);
PG_FUNCTION_INFO_V1(g_int_union);
PG_FUNCTION_INFO_V1(g_int_same);
PG_FUNCTION_INFO_V1(g_int_options);
/*
** The GiST Consistent method for _intments
** Should return false if for all data items x below entry,
** the predicate x op query == false, where op is the oper
** corresponding to strategy in the pg_amop table.
*/
Datum
g_int_consistent(PG_FUNCTION_ARGS)
{
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
ArrayType *query = PG_GETARG_ARRAYTYPE_P_COPY(1);
StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);
/* Oid subtype = PG_GETARG_OID(3); */
bool *recheck = (bool *) PG_GETARG_POINTER(4);
bool retval = false; /* silence compiler warning */
/* this is exact except for RTSameStrategyNumber */
*recheck = (strategy == RTSameStrategyNumber);
if (strategy == BooleanSearchStrategy)
{
retval = execconsistent((QUERYTYPE *) query,
(ArrayType *) DatumGetPointer(entry->key),
GIST_LEAF(entry));
pfree(query);
PG_RETURN_BOOL(retval);
}
/* sort query for fast search, key is already sorted */
CHECKARRVALID(query);
PREPAREARR(query);
switch (strategy)
{
case RTOverlapStrategyNumber:
retval = inner_int_overlap((ArrayType *) DatumGetPointer(entry->key),
query);
break;
case RTSameStrategyNumber:
if (GIST_LEAF(entry))
DirectFunctionCall3(g_int_same,
entry->key,
PointerGetDatum(query),
PointerGetDatum(&retval));
else
retval = inner_int_contains((ArrayType *) DatumGetPointer(entry->key),
query);
break;
case RTContainsStrategyNumber:
case RTOldContainsStrategyNumber:
retval = inner_int_contains((ArrayType *) DatumGetPointer(entry->key),
query);
break;
case RTContainedByStrategyNumber:
case RTOldContainedByStrategyNumber:
/*
* This code is unreachable as of intarray 1.4, because the <@
* operator has been removed from the opclass. We keep it for now
* to support older versions of the SQL definitions.
*/
if (GIST_LEAF(entry))
retval = inner_int_contains(query,
(ArrayType *) DatumGetPointer(entry->key));
else
{
/*
* Unfortunately, because empty arrays could be anywhere in
* the index, we must search the whole tree.
*/
retval = true;
}
break;
default:
retval = false;
}
pfree(query);
PG_RETURN_BOOL(retval);
}
Datum
g_int_union(PG_FUNCTION_ARGS)
{
GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
int *size = (int *) PG_GETARG_POINTER(1);
int32 i,
*ptr;
ArrayType *res;
int totlen = 0;
for (i = 0; i < entryvec->n; i++)
{
ArrayType *ent = GETENTRY(entryvec, i);
CHECKARRVALID(ent);
totlen += ARRNELEMS(ent);
}
res = new_intArrayType(totlen);
ptr = ARRPTR(res);
for (i = 0; i < entryvec->n; i++)
{
ArrayType *ent = GETENTRY(entryvec, i);
int nel;
nel = ARRNELEMS(ent);
memcpy(ptr, ARRPTR(ent), nel * sizeof(int32));
ptr += nel;
}
QSORT(res, 1);
res = _int_unique(res);
*size = VARSIZE(res);
PG_RETURN_POINTER(res);
}
/*
** GiST Compress and Decompress methods
*/
Datum
g_int_compress(PG_FUNCTION_ARGS)
{
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
GISTENTRY *retval;
ArrayType *r;
int num_ranges = G_INT_GET_NUMRANGES();
int len,
lenr;
int *dr;
int i,
j,
cand;
int64 min;
if (entry->leafkey)
{
r = DatumGetArrayTypePCopy(entry->key);
CHECKARRVALID(r);
PREPAREARR(r);
if (ARRNELEMS(r) >= 2 * num_ranges)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("input array is too big (%d maximum allowed, %d current), use gist__intbig_ops opclass instead",
2 * num_ranges - 1, ARRNELEMS(r))));
retval = palloc(sizeof(GISTENTRY));
gistentryinit(*retval, PointerGetDatum(r),
entry->rel, entry->page, entry->offset, false);
PG_RETURN_POINTER(retval);
}
/*
* leaf entries never compress one more time, only when entry->leafkey
* ==true, so now we work only with internal keys
*/
r = DatumGetArrayTypeP(entry->key);
CHECKARRVALID(r);
if (ARRISEMPTY(r))
{
if (r != (ArrayType *) DatumGetPointer(entry->key))
pfree(r);
PG_RETURN_POINTER(entry);
}
if ((len = ARRNELEMS(r)) >= 2 * num_ranges)
{ /* compress */
if (r == (ArrayType *) DatumGetPointer(entry->key))
r = DatumGetArrayTypePCopy(entry->key);
r = resize_intArrayType(r, 2 * (len));
dr = ARRPTR(r);
/*
* "len" at this point is the number of ranges we will construct.
* "lenr" is the number of ranges we must eventually remove by
* merging, we must be careful to remove no more than this number.
*/
lenr = len - num_ranges;
/*
* Initially assume we can merge consecutive ints into a range. but we
* must count every value removed and stop when lenr runs out
*/
for (j = i = len - 1; i > 0 && lenr > 0; i--, j--)
{
int r_end = dr[i];
int r_start = r_end;
while (i > 0 && lenr > 0 && dr[i - 1] == r_start - 1)
--r_start, --i, --lenr;
dr[2 * j] = r_start;
dr[2 * j + 1] = r_end;
}
/* just copy the rest, if any, as trivial ranges */
for (; i >= 0; i--, j--)
dr[2 * j] = dr[2 * j + 1] = dr[i];
if (++j)
{
/*
* shunt everything down to start at the right place
*/
memmove(&dr[0], &dr[2 * j], 2 * (len - j) * sizeof(int32));
}
/*
* make "len" be number of array elements, not ranges
*/
len = 2 * (len - j);
cand = 1;
while (len > num_ranges * 2)
{
min = PG_INT64_MAX;
for (i = 2; i < len; i += 2)
if (min > ((int64) dr[i] - (int64) dr[i - 1]))
{
min = ((int64) dr[i] - (int64) dr[i - 1]);
cand = i;
}
memmove(&dr[cand - 1], &dr[cand + 1], (len - cand - 1) * sizeof(int32));
len -= 2;
}
/*
* check sparseness of result
*/
lenr = internal_size(dr, len);
if (lenr < 0 || lenr > MAXNUMELTS)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("data is too sparse, recreate index using gist__intbig_ops opclass instead")));
r = resize_intArrayType(r, len);
retval = palloc(sizeof(GISTENTRY));
gistentryinit(*retval, PointerGetDatum(r),
entry->rel, entry->page, entry->offset, false);
PG_RETURN_POINTER(retval);
}
else
PG_RETURN_POINTER(entry);
}
Datum
g_int_decompress(PG_FUNCTION_ARGS)
{
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
GISTENTRY *retval;
ArrayType *r;
int num_ranges = G_INT_GET_NUMRANGES();
int *dr,
lenr;
ArrayType *in;
int lenin;
int *din;
int i;
in = DatumGetArrayTypeP(entry->key);
CHECKARRVALID(in);
if (ARRISEMPTY(in))
{
if (in != (ArrayType *) DatumGetPointer(entry->key))
{
retval = palloc(sizeof(GISTENTRY));
gistentryinit(*retval, PointerGetDatum(in),
entry->rel, entry->page, entry->offset, false);
PG_RETURN_POINTER(retval);
}
PG_RETURN_POINTER(entry);
}
lenin = ARRNELEMS(in);
if (lenin < 2 * num_ranges)
{ /* not compressed value */
if (in != (ArrayType *) DatumGetPointer(entry->key))
{
retval = palloc(sizeof(GISTENTRY));
gistentryinit(*retval, PointerGetDatum(in),
entry->rel, entry->page, entry->offset, false);
PG_RETURN_POINTER(retval);
}
PG_RETURN_POINTER(entry);
}
din = ARRPTR(in);
lenr = internal_size(din, lenin);
if (lenr < 0 || lenr > MAXNUMELTS)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("compressed array is too big, recreate index using gist__intbig_ops opclass instead")));
r = new_intArrayType(lenr);
dr = ARRPTR(r);
for (i = 0; i < lenin; i += 2)
{
/* use int64 for j in case din[i + 1] is INT_MAX */
for (int64 j = din[i]; j <= din[i + 1]; j++)
if ((!i) || *(dr - 1) != j)
*dr++ = (int) j;
}
if (in != (ArrayType *) DatumGetPointer(entry->key))
pfree(in);
retval = palloc(sizeof(GISTENTRY));
gistentryinit(*retval, PointerGetDatum(r),
entry->rel, entry->page, entry->offset, false);
PG_RETURN_POINTER(retval);
}
/*
** The GiST Penalty method for _intments
*/
Datum
g_int_penalty(PG_FUNCTION_ARGS)
{
GISTENTRY *origentry = (GISTENTRY *) PG_GETARG_POINTER(0);
GISTENTRY *newentry = (GISTENTRY *) PG_GETARG_POINTER(1);
float *result = (float *) PG_GETARG_POINTER(2);
ArrayType *ud;
float tmp1,
tmp2;
ud = inner_int_union((ArrayType *) DatumGetPointer(origentry->key),
(ArrayType *) DatumGetPointer(newentry->key));
rt__int_size(ud, &tmp1);
rt__int_size((ArrayType *) DatumGetPointer(origentry->key), &tmp2);
*result = tmp1 - tmp2;
pfree(ud);
PG_RETURN_POINTER(result);
}
Datum
g_int_same(PG_FUNCTION_ARGS)
{
ArrayType *a = PG_GETARG_ARRAYTYPE_P(0);
ArrayType *b = PG_GETARG_ARRAYTYPE_P(1);
bool *result = (bool *) PG_GETARG_POINTER(2);
int32 n = ARRNELEMS(a);
int32 *da,
*db;
CHECKARRVALID(a);
CHECKARRVALID(b);
if (n != ARRNELEMS(b))
{
*result = false;
PG_RETURN_POINTER(result);
}
*result = true;
da = ARRPTR(a);
db = ARRPTR(b);
while (n--)
{
if (*da++ != *db++)
{
*result = false;
break;
}
}
PG_RETURN_POINTER(result);
}
/*****************************************************************
** Common GiST Method
*****************************************************************/
typedef struct
{
OffsetNumber pos;
float cost;
} SPLITCOST;
static int
comparecost(const void *a, const void *b)
{
if (((const SPLITCOST *) a)->cost == ((const SPLITCOST *) b)->cost)
return 0;
else
return (((const SPLITCOST *) a)->cost > ((const SPLITCOST *) b)->cost) ? 1 : -1;
}
/*
** The GiST PickSplit method for _intments
** We use Guttman's poly time split algorithm
*/
Datum
g_int_picksplit(PG_FUNCTION_ARGS)
{
GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
GIST_SPLITVEC *v = (GIST_SPLITVEC *) PG_GETARG_POINTER(1);
OffsetNumber i,
j;
ArrayType *datum_alpha,
*datum_beta;
ArrayType *datum_l,
*datum_r;
ArrayType *union_d,
*union_dl,
*union_dr;
ArrayType *inter_d;
bool firsttime;
float size_alpha,
size_beta,
size_union,
size_inter;
float size_waste,
waste;
float size_l,
size_r;
int nbytes;
OffsetNumber seed_1 = 0,
seed_2 = 0;
OffsetNumber *left,
*right;
OffsetNumber maxoff;
SPLITCOST *costvector;
#ifdef GIST_DEBUG
elog(DEBUG3, "--------picksplit %d", entryvec->n);
#endif
maxoff = entryvec->n - 2;
nbytes = (maxoff + 2) * sizeof(OffsetNumber);
v->spl_left = (OffsetNumber *) palloc(nbytes);
v->spl_right = (OffsetNumber *) palloc(nbytes);
firsttime = true;
waste = 0.0;
for (i = FirstOffsetNumber; i < maxoff; i = OffsetNumberNext(i))
{
datum_alpha = GETENTRY(entryvec, i);
for (j = OffsetNumberNext(i); j <= maxoff; j = OffsetNumberNext(j))
{
datum_beta = GETENTRY(entryvec, j);
/* compute the wasted space by unioning these guys */
/* size_waste = size_union - size_inter; */
union_d = inner_int_union(datum_alpha, datum_beta);
rt__int_size(union_d, &size_union);
inter_d = inner_int_inter(datum_alpha, datum_beta);
rt__int_size(inter_d, &size_inter);
size_waste = size_union - size_inter;
pfree(union_d);
pfree(inter_d);
/*
* are these a more promising split that what we've already seen?
*/
if (size_waste > waste || firsttime)
{
waste = size_waste;
seed_1 = i;
seed_2 = j;
firsttime = false;
}
}
}
left = v->spl_left;
v->spl_nleft = 0;
right = v->spl_right;
v->spl_nright = 0;
if (seed_1 == 0 || seed_2 == 0)
{
seed_1 = 1;
seed_2 = 2;
}
datum_alpha = GETENTRY(entryvec, seed_1);
datum_l = copy_intArrayType(datum_alpha);
rt__int_size(datum_l, &size_l);
datum_beta = GETENTRY(entryvec, seed_2);
datum_r = copy_intArrayType(datum_beta);
rt__int_size(datum_r, &size_r);
maxoff = OffsetNumberNext(maxoff);
/*
* sort entries
*/
costvector = (SPLITCOST *) palloc(sizeof(SPLITCOST) * maxoff);
for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
{
costvector[i - 1].pos = i;
datum_alpha = GETENTRY(entryvec, i);
union_d = inner_int_union(datum_l, datum_alpha);
rt__int_size(union_d, &size_alpha);
pfree(union_d);
union_d = inner_int_union(datum_r, datum_alpha);
rt__int_size(union_d, &size_beta);
pfree(union_d);
costvector[i - 1].cost = fabsf((size_alpha - size_l) - (size_beta - size_r));
}
qsort(costvector, maxoff, sizeof(SPLITCOST), comparecost);
/*
* Now split up the regions between the two seeds. An important property
* of this split algorithm is that the split vector v has the indices of
* items to be split in order in its left and right vectors. We exploit
* this property by doing a merge in the code that actually splits the
* page.
*
* For efficiency, we also place the new index tuple in this loop. This is
* handled at the very end, when we have placed all the existing tuples
* and i == maxoff + 1.
*/
for (j = 0; j < maxoff; j++)
{
i = costvector[j].pos;
/*
* If we've already decided where to place this item, just put it on
* the right list. Otherwise, we need to figure out which page needs
* the least enlargement in order to store the item.
*/
if (i == seed_1)
{
*left++ = i;
v->spl_nleft++;
continue;
}
else if (i == seed_2)
{
*right++ = i;
v->spl_nright++;
continue;
}
/* okay, which page needs least enlargement? */
datum_alpha = GETENTRY(entryvec, i);
union_dl = inner_int_union(datum_l, datum_alpha);
union_dr = inner_int_union(datum_r, datum_alpha);
rt__int_size(union_dl, &size_alpha);
rt__int_size(union_dr, &size_beta);
/* pick which page to add it to */
if (size_alpha - size_l < size_beta - size_r + WISH_F(v->spl_nleft, v->spl_nright, 0.01))
{
pfree(datum_l);
pfree(union_dr);
datum_l = union_dl;
size_l = size_alpha;
*left++ = i;
v->spl_nleft++;
}
else
{
pfree(datum_r);
pfree(union_dl);
datum_r = union_dr;
size_r = size_beta;
*right++ = i;
v->spl_nright++;
}
}
pfree(costvector);
*right = *left = FirstOffsetNumber;
v->spl_ldatum = PointerGetDatum(datum_l);
v->spl_rdatum = PointerGetDatum(datum_r);
PG_RETURN_POINTER(v);
}
Datum
g_int_options(PG_FUNCTION_ARGS)
{
local_relopts *relopts = (local_relopts *) PG_GETARG_POINTER(0);
init_local_reloptions(relopts, sizeof(GISTIntArrayOptions));
add_local_int_reloption(relopts, "numranges",
"number of ranges for compression",
G_INT_NUMRANGES_DEFAULT, 1, G_INT_NUMRANGES_MAX,
offsetof(GISTIntArrayOptions, num_ranges));
PG_RETURN_VOID();
}