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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 22:46:16 +00:00
parent 138fdf32bb
commit 33feb55c47
8 changed files with 100 additions and 82 deletions
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39
contrib/intarray/_intbig_gist.c
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@ -20,16 +20,25 @@ Datum g_intbig_picksplit(PG_FUNCTION_ARGS);
Datum g_intbig_union(PG_FUNCTION_ARGS);
Datum g_intbig_same(PG_FUNCTION_ARGS);
#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
};
PG_FUNCTION_INFO_V1(_intbig_in);
Datum _intbig_in(PG_FUNCTION_ARGS);
@ -205,8 +214,7 @@ sizebitvec(BITVECP sign)
i;
LOOPBYTE(
size += SUMBIT(sign);
sign = (BITVECP) (((char *) sign) + 1);
size += number_of_ones[(unsigned char) sign[i]];
);
return size;
}
@ -215,11 +223,12 @@ 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;
}