postgresql/contrib/hstore/hstore_gist.c
Heikki Linnakangas 5028f22f6e Switch to CRC-32C in WAL and other places.
The old algorithm was found to not be the usual CRC-32 algorithm, used by
Ethernet et al. We were using a non-reflected lookup table with code meant
for a reflected lookup table. That's a strange combination that AFAICS does
not correspond to any bit-wise CRC calculation, which makes it difficult to
reason about its properties. Although it has worked well in practice, seems
safer to use a well-known algorithm.

Since we're changing the algorithm anyway, we might as well choose a
different polynomial. The Castagnoli polynomial has better error-correcting
properties than the traditional CRC-32 polynomial, even if we had
implemented it correctly. Another reason for picking that is that some new
CPUs have hardware support for calculating CRC-32C, but not CRC-32, let
alone our strange variant of it. This patch doesn't add any support for such
hardware, but a future patch could now do that.

The old algorithm is kept around for tsquery and pg_trgm, which use the
values in indexes that need to remain compatible so that pg_upgrade works.
While we're at it, share the old lookup table for CRC-32 calculation
between hstore, ltree and core. They all use the same table, so might as
well.
2014-11-04 11:39:48 +02:00

602 lines
13 KiB
C

/*
* contrib/hstore/hstore_gist.c
*/
#include "postgres.h"
#include "access/gist.h"
#include "access/skey.h"
#include "catalog/pg_type.h"
#include "utils/pg_crc.h"
#include "hstore.h"
/* bigint defines */
#define BITBYTE 8
#define SIGLENINT 4 /* >122 => key will toast, so very slow!!! */
#define SIGLEN ( sizeof(int)*SIGLENINT )
#define SIGLENBIT (SIGLEN*BITBYTE)
typedef char BITVEC[SIGLEN];
typedef char *BITVECP;
#define SIGPTR(x) ( (BITVECP) ARR_DATA_PTR(x) )
#define LOOPBYTE \
for(i=0;i<SIGLEN;i++)
#define LOOPBIT \
for(i=0;i<SIGLENBIT;i++)
/* beware of multiple evaluation of arguments to these macros! */
#define GETBYTE(x,i) ( *( (BITVECP)(x) + (int)( (i) / BITBYTE ) ) )
#define GETBITBYTE(x,i) ( (*((char*)(x)) >> (i)) & 0x01 )
#define CLRBIT(x,i) GETBYTE(x,i) &= ~( 0x01 << ( (i) % BITBYTE ) )
#define SETBIT(x,i) GETBYTE(x,i) |= ( 0x01 << ( (i) % BITBYTE ) )
#define GETBIT(x,i) ( (GETBYTE(x,i) >> ( (i) % BITBYTE )) & 0x01 )
#define HASHVAL(val) (((unsigned int)(val)) % SIGLENBIT)
#define HASH(sign, val) SETBIT((sign), HASHVAL(val))
typedef struct
{
int32 vl_len_; /* varlena header (do not touch directly!) */
int32 flag;
char data[1];
} GISTTYPE;
#define ALLISTRUE 0x04
#define ISALLTRUE(x) ( ((GISTTYPE*)x)->flag & ALLISTRUE )
#define GTHDRSIZE (VARHDRSZ + sizeof(int32))
#define CALCGTSIZE(flag) ( GTHDRSIZE+(((flag) & ALLISTRUE) ? 0 : SIGLEN) )
#define GETSIGN(x) ( (BITVECP)( (char*)x+GTHDRSIZE ) )
#define SUMBIT(val) ( \
GETBITBYTE((val),0) + \
GETBITBYTE((val),1) + \
GETBITBYTE((val),2) + \
GETBITBYTE((val),3) + \
GETBITBYTE((val),4) + \
GETBITBYTE((val),5) + \
GETBITBYTE((val),6) + \
GETBITBYTE((val),7) \
)
#define GETENTRY(vec,pos) ((GISTTYPE *) DatumGetPointer((vec)->vector[(pos)].key))
#define WISH_F(a,b,c) (double)( -(double)(((a)-(b))*((a)-(b))*((a)-(b)))*(c) )
/* shorthand for calculating CRC-32 of a single chunk of data. */
static pg_crc32
crc32_sz(char *buf, int size)
{
pg_crc32 crc;
INIT_TRADITIONAL_CRC32(crc);
COMP_TRADITIONAL_CRC32(crc, buf, size);
FIN_TRADITIONAL_CRC32(crc);
return crc;
}
PG_FUNCTION_INFO_V1(ghstore_in);
PG_FUNCTION_INFO_V1(ghstore_out);
Datum
ghstore_in(PG_FUNCTION_ARGS)
{
elog(ERROR, "Not implemented");
PG_RETURN_DATUM(0);
}
Datum
ghstore_out(PG_FUNCTION_ARGS)
{
elog(ERROR, "Not implemented");
PG_RETURN_DATUM(0);
}
PG_FUNCTION_INFO_V1(ghstore_consistent);
PG_FUNCTION_INFO_V1(ghstore_compress);
PG_FUNCTION_INFO_V1(ghstore_decompress);
PG_FUNCTION_INFO_V1(ghstore_penalty);
PG_FUNCTION_INFO_V1(ghstore_picksplit);
PG_FUNCTION_INFO_V1(ghstore_union);
PG_FUNCTION_INFO_V1(ghstore_same);
Datum
ghstore_compress(PG_FUNCTION_ARGS)
{
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
GISTENTRY *retval = entry;
if (entry->leafkey)
{
GISTTYPE *res = (GISTTYPE *) palloc0(CALCGTSIZE(0));
HStore *val = DatumGetHStoreP(entry->key);
HEntry *hsent = ARRPTR(val);
char *ptr = STRPTR(val);
int count = HS_COUNT(val);
int i;
SET_VARSIZE(res, CALCGTSIZE(0));
for (i = 0; i < count; ++i)
{
int h;
h = crc32_sz((char *) HS_KEY(hsent, ptr, i), HS_KEYLEN(hsent, i));
HASH(GETSIGN(res), h);
if (!HS_VALISNULL(hsent, i))
{
h = crc32_sz((char *) HS_VAL(hsent, ptr, i), HS_VALLEN(hsent, i));
HASH(GETSIGN(res), h);
}
}
retval = (GISTENTRY *) palloc(sizeof(GISTENTRY));
gistentryinit(*retval, PointerGetDatum(res),
entry->rel, entry->page,
entry->offset,
FALSE);
}
else if (!ISALLTRUE(DatumGetPointer(entry->key)))
{
int32 i;
GISTTYPE *res;
BITVECP sign = GETSIGN(DatumGetPointer(entry->key));
LOOPBYTE
{
if ((sign[i] & 0xff) != 0xff)
PG_RETURN_POINTER(retval);
}
res = (GISTTYPE *) palloc(CALCGTSIZE(ALLISTRUE));
SET_VARSIZE(res, CALCGTSIZE(ALLISTRUE));
res->flag = ALLISTRUE;
retval = (GISTENTRY *) palloc(sizeof(GISTENTRY));
gistentryinit(*retval, PointerGetDatum(res),
entry->rel, entry->page,
entry->offset,
FALSE);
}
PG_RETURN_POINTER(retval);
}
/*
* Since type ghstore isn't toastable (and doesn't need to be),
* this function can be a no-op.
*/
Datum
ghstore_decompress(PG_FUNCTION_ARGS)
{
PG_RETURN_POINTER(PG_GETARG_POINTER(0));
}
Datum
ghstore_same(PG_FUNCTION_ARGS)
{
GISTTYPE *a = (GISTTYPE *) PG_GETARG_POINTER(0);
GISTTYPE *b = (GISTTYPE *) PG_GETARG_POINTER(1);
bool *result = (bool *) PG_GETARG_POINTER(2);
if (ISALLTRUE(a) && ISALLTRUE(b))
*result = true;
else if (ISALLTRUE(a))
*result = false;
else if (ISALLTRUE(b))
*result = false;
else
{
int32 i;
BITVECP sa = GETSIGN(a),
sb = GETSIGN(b);
*result = true;
LOOPBYTE
{
if (sa[i] != sb[i])
{
*result = false;
break;
}
}
}
PG_RETURN_POINTER(result);
}
static int32
sizebitvec(BITVECP sign)
{
int32 size = 0,
i;
LOOPBYTE
{
size += SUMBIT(sign);
sign = (BITVECP) (((char *) sign) + 1);
}
return size;
}
static int
hemdistsign(BITVECP a, BITVECP b)
{
int i,
dist = 0;
LOOPBIT
{
if (GETBIT(a, i) != GETBIT(b, i))
dist++;
}
return dist;
}
static int
hemdist(GISTTYPE *a, GISTTYPE *b)
{
if (ISALLTRUE(a))
{
if (ISALLTRUE(b))
return 0;
else
return SIGLENBIT - sizebitvec(GETSIGN(b));
}
else if (ISALLTRUE(b))
return SIGLENBIT - sizebitvec(GETSIGN(a));
return hemdistsign(GETSIGN(a), GETSIGN(b));
}
static int32
unionkey(BITVECP sbase, GISTTYPE *add)
{
int32 i;
BITVECP sadd = GETSIGN(add);
if (ISALLTRUE(add))
return 1;
LOOPBYTE
sbase[i] |= sadd[i];
return 0;
}
Datum
ghstore_union(PG_FUNCTION_ARGS)
{
GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
int32 len = entryvec->n;
int *size = (int *) PG_GETARG_POINTER(1);
BITVEC base;
int32 i;
int32 flag = 0;
GISTTYPE *result;
MemSet((void *) base, 0, sizeof(BITVEC));
for (i = 0; i < len; i++)
{
if (unionkey(base, GETENTRY(entryvec, i)))
{
flag = ALLISTRUE;
break;
}
}
len = CALCGTSIZE(flag);
result = (GISTTYPE *) palloc(len);
SET_VARSIZE(result, len);
result->flag = flag;
if (!ISALLTRUE(result))
memcpy((void *) GETSIGN(result), (void *) base, sizeof(BITVEC));
*size = len;
PG_RETURN_POINTER(result);
}
Datum
ghstore_penalty(PG_FUNCTION_ARGS)
{
GISTENTRY *origentry = (GISTENTRY *) PG_GETARG_POINTER(0); /* always ISSIGNKEY */
GISTENTRY *newentry = (GISTENTRY *) PG_GETARG_POINTER(1);
float *penalty = (float *) PG_GETARG_POINTER(2);
GISTTYPE *origval = (GISTTYPE *) DatumGetPointer(origentry->key);
GISTTYPE *newval = (GISTTYPE *) DatumGetPointer(newentry->key);
*penalty = hemdist(origval, newval);
PG_RETURN_POINTER(penalty);
}
typedef struct
{
OffsetNumber pos;
int32 cost;
} SPLITCOST;
static int
comparecost(const void *a, const void *b)
{
return ((const SPLITCOST *) a)->cost - ((const SPLITCOST *) b)->cost;
}
Datum
ghstore_picksplit(PG_FUNCTION_ARGS)
{
GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
OffsetNumber maxoff = entryvec->n - 2;
GIST_SPLITVEC *v = (GIST_SPLITVEC *) PG_GETARG_POINTER(1);
OffsetNumber k,
j;
GISTTYPE *datum_l,
*datum_r;
BITVECP union_l,
union_r;
int32 size_alpha,
size_beta;
int32 size_waste,
waste = -1;
int32 nbytes;
OffsetNumber seed_1 = 0,
seed_2 = 0;
OffsetNumber *left,
*right;
BITVECP ptr;
int i;
SPLITCOST *costvector;
GISTTYPE *_k,
*_j;
nbytes = (maxoff + 2) * sizeof(OffsetNumber);
v->spl_left = (OffsetNumber *) palloc(nbytes);
v->spl_right = (OffsetNumber *) palloc(nbytes);
for (k = FirstOffsetNumber; k < maxoff; k = OffsetNumberNext(k))
{
_k = GETENTRY(entryvec, k);
for (j = OffsetNumberNext(k); j <= maxoff; j = OffsetNumberNext(j))
{
size_waste = hemdist(_k, GETENTRY(entryvec, j));
if (size_waste > waste)
{
waste = size_waste;
seed_1 = k;
seed_2 = j;
}
}
}
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;
}
/* form initial .. */
if (ISALLTRUE(GETENTRY(entryvec, seed_1)))
{
datum_l = (GISTTYPE *) palloc(GTHDRSIZE);
SET_VARSIZE(datum_l, GTHDRSIZE);
datum_l->flag = ALLISTRUE;
}
else
{
datum_l = (GISTTYPE *) palloc(GTHDRSIZE + SIGLEN);
SET_VARSIZE(datum_l, GTHDRSIZE + SIGLEN);
datum_l->flag = 0;
memcpy((void *) GETSIGN(datum_l), (void *) GETSIGN(GETENTRY(entryvec, seed_1)), sizeof(BITVEC))
;
}
if (ISALLTRUE(GETENTRY(entryvec, seed_2)))
{
datum_r = (GISTTYPE *) palloc(GTHDRSIZE);
SET_VARSIZE(datum_r, GTHDRSIZE);
datum_r->flag = ALLISTRUE;
}
else
{
datum_r = (GISTTYPE *) palloc(GTHDRSIZE + SIGLEN);
SET_VARSIZE(datum_r, GTHDRSIZE + SIGLEN);
datum_r->flag = 0;
memcpy((void *) GETSIGN(datum_r), (void *) GETSIGN(GETENTRY(entryvec, seed_2)), sizeof(BITVEC));
}
maxoff = OffsetNumberNext(maxoff);
/* sort before ... */
costvector = (SPLITCOST *) palloc(sizeof(SPLITCOST) * maxoff);
for (j = FirstOffsetNumber; j <= maxoff; j = OffsetNumberNext(j))
{
costvector[j - 1].pos = j;
_j = GETENTRY(entryvec, j);
size_alpha = hemdist(datum_l, _j);
size_beta = hemdist(datum_r, _j);
costvector[j - 1].cost = abs(size_alpha - size_beta);
}
qsort((void *) costvector, maxoff, sizeof(SPLITCOST), comparecost);
union_l = GETSIGN(datum_l);
union_r = GETSIGN(datum_r);
for (k = 0; k < maxoff; k++)
{
j = costvector[k].pos;
if (j == seed_1)
{
*left++ = j;
v->spl_nleft++;
continue;
}
else if (j == seed_2)
{
*right++ = j;
v->spl_nright++;
continue;
}
_j = GETENTRY(entryvec, j);
size_alpha = hemdist(datum_l, _j);
size_beta = hemdist(datum_r, _j);
if (size_alpha < size_beta + WISH_F(v->spl_nleft, v->spl_nright, 0.0001))
{
if (ISALLTRUE(datum_l) || ISALLTRUE(_j))
{
if (!ISALLTRUE(datum_l))
MemSet((void *) union_l, 0xff, sizeof(BITVEC));
}
else
{
ptr = GETSIGN(_j);
LOOPBYTE
union_l[i] |= ptr[i];
}
*left++ = j;
v->spl_nleft++;
}
else
{
if (ISALLTRUE(datum_r) || ISALLTRUE(_j))
{
if (!ISALLTRUE(datum_r))
MemSet((void *) union_r, 0xff, sizeof(BITVEC));
}
else
{
ptr = GETSIGN(_j);
LOOPBYTE
union_r[i] |= ptr[i];
}
*right++ = j;
v->spl_nright++;
}
}
*right = *left = FirstOffsetNumber;
v->spl_ldatum = PointerGetDatum(datum_l);
v->spl_rdatum = PointerGetDatum(datum_r);
PG_RETURN_POINTER(v);
}
Datum
ghstore_consistent(PG_FUNCTION_ARGS)
{
GISTTYPE *entry = (GISTTYPE *) DatumGetPointer(((GISTENTRY *) PG_GETARG_POINTER(0))->key);
StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);
/* Oid subtype = PG_GETARG_OID(3); */
bool *recheck = (bool *) PG_GETARG_POINTER(4);
bool res = true;
BITVECP sign;
/* All cases served by this function are inexact */
*recheck = true;
if (ISALLTRUE(entry))
PG_RETURN_BOOL(true);
sign = GETSIGN(entry);
if (strategy == HStoreContainsStrategyNumber ||
strategy == HStoreOldContainsStrategyNumber)
{
HStore *query = PG_GETARG_HS(1);
HEntry *qe = ARRPTR(query);
char *qv = STRPTR(query);
int count = HS_COUNT(query);
int i;
for (i = 0; res && i < count; ++i)
{
int crc = crc32_sz((char *) HS_KEY(qe, qv, i), HS_KEYLEN(qe, i));
if (GETBIT(sign, HASHVAL(crc)))
{
if (!HS_VALISNULL(qe, i))
{
crc = crc32_sz((char *) HS_VAL(qe, qv, i), HS_VALLEN(qe, i));
if (!GETBIT(sign, HASHVAL(crc)))
res = false;
}
}
else
res = false;
}
}
else if (strategy == HStoreExistsStrategyNumber)
{
text *query = PG_GETARG_TEXT_PP(1);
int crc = crc32_sz(VARDATA_ANY(query), VARSIZE_ANY_EXHDR(query));
res = (GETBIT(sign, HASHVAL(crc))) ? true : false;
}
else if (strategy == HStoreExistsAllStrategyNumber)
{
ArrayType *query = PG_GETARG_ARRAYTYPE_P(1);
Datum *key_datums;
bool *key_nulls;
int key_count;
int i;
deconstruct_array(query,
TEXTOID, -1, false, 'i',
&key_datums, &key_nulls, &key_count);
for (i = 0; res && i < key_count; ++i)
{
int crc;
if (key_nulls[i])
continue;
crc = crc32_sz(VARDATA(key_datums[i]), VARSIZE(key_datums[i]) - VARHDRSZ);
if (!(GETBIT(sign, HASHVAL(crc))))
res = FALSE;
}
}
else if (strategy == HStoreExistsAnyStrategyNumber)
{
ArrayType *query = PG_GETARG_ARRAYTYPE_P(1);
Datum *key_datums;
bool *key_nulls;
int key_count;
int i;
deconstruct_array(query,
TEXTOID, -1, false, 'i',
&key_datums, &key_nulls, &key_count);
res = FALSE;
for (i = 0; !res && i < key_count; ++i)
{
int crc;
if (key_nulls[i])
continue;
crc = crc32_sz(VARDATA(key_datums[i]), VARSIZE(key_datums[i]) - VARHDRSZ);
if (GETBIT(sign, HASHVAL(crc)))
res = TRUE;
}
}
else
elog(ERROR, "Unsupported strategy number: %d", strategy);
PG_RETURN_BOOL(res);
}