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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2006-01-20 22:46:40 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2006-01-20 22:46:40 +0000 |
| commit | 4977c2b31b26f5a738f5f85dd03c5275ad3ce058 (patch) | |
| tree | c120b7b744c05333d6a17675823fcaabe3d3df40 /contrib/intarray/_intbig_gist.c | |
| parent | 4a651c97055c700259965f6aa71da68440a48663 (diff) | |
| download | postgresql-4977c2b31b26f5a738f5f85dd03c5275ad3ce058.tar.gz postgresql-4977c2b31b26f5a738f5f85dd03c5275ad3ce058.zip | |
Replace bitwise looping with bytewise looping in hemdistsign and
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.
Diffstat (limited to 'contrib/intarray/_intbig_gist.c')
| -rw-r--r-- | contrib/intarray/_intbig_gist.c | 39 |
1 files changed, 24 insertions, 15 deletions
diff --git a/contrib/intarray/_intbig_gist.c b/contrib/intarray/_intbig_gist.c index 237281aec5b..c49a2aab534 100644 --- a/contrib/intarray/_intbig_gist.c +++ b/contrib/intarray/_intbig_gist.c @@ -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); @@ -194,8 +203,7 @@ sizebitvec(BITVECP sign) i; LOOPBYTE( - size += SUMBIT(sign); - sign = (BITVECP) (((char *) sign) + 1); + size += number_of_ones[(unsigned char) sign[i]]; ); return size; } @@ -204,11 +212,12 @@ 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; } |