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Replace bitwise looping with bytewise looping in hemdistsign and

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sizebitvec of tsearch2, as well as identical code in several other
contrib modules.  This provided about a 20X speedup in building a
large tsearch2 index ... didn't try to measure its effects for other
operations.  Thanks to Stephan Vollmer for providing a test case.
This commit is contained in:
Tom Lane
2006-01-20 22:46:40 +00:00
parent 4a651c9705
commit 4977c2b31b
8 changed files with 100 additions and 82 deletions
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40
contrib/tsearch2/gistidx.c
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@ -43,16 +43,26 @@ PG_FUNCTION_INFO_V1(gtsvector_picksplit);
Datum gtsvector_picksplit(PG_FUNCTION_ARGS);
#define GETENTRY(vec,pos) ((GISTTYPE *) DatumGetPointer((vec)->vector[(pos)].key))
#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) \
)
/* Number of one-bits in an unsigned byte */
static const uint8 number_of_ones[256] = {
0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8
};
static int4 sizebitvec(BITVECP sign);
@ -436,8 +446,7 @@ sizebitvec(BITVECP sign)
i;
LOOPBYTE(
size += SUMBIT(*(char *) sign);
sign = (BITVECP) (((char *) sign) + 1);
size += number_of_ones[(unsigned char) sign[i]];
);
return size;
}
@ -446,11 +455,12 @@ static int
hemdistsign(BITVECP a, BITVECP b)
{
int i,
diff,
dist = 0;
LOOPBIT(
if (GETBIT(a, i) != GETBIT(b, i))
dist++;
LOOPBYTE(
diff = (unsigned char) (a[i] ^ b[i]);
dist += number_of_ones[diff];
);
return dist;
}