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Avoid using text_to_cstring() in levenshtein functions. 

Operating directly on the underlying varlena saves palloc and memcpy
overhead, which testing shows to be significant.

Extracted from a larger patch by Alexander Korotkov.
This commit is contained in:
Robert Haas 2010-07-29 20:11:48 +00:00
parent aab353a60b
commit 980341b3c2
1 changed files with 11 additions and 11 deletions
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22
contrib/fuzzystrmatch/fuzzystrmatch.c
View File

@ -5,7 +5,7 @@
* *
* Joe Conway <mail@joeconway.com> * Joe Conway <mail@joeconway.com>
* *
* $PostgreSQL: pgsql/contrib/fuzzystrmatch/fuzzystrmatch.c,v 1.32 2010/01/02 16:57:32 momjian Exp $ * $PostgreSQL: pgsql/contrib/fuzzystrmatch/fuzzystrmatch.c,v 1.33 2010/07/29 20:11:48 rhaas Exp $
* Copyright (c) 2001-2010, PostgreSQL Global Development Group * Copyright (c) 2001-2010, PostgreSQL Global Development Group
* ALL RIGHTS RESERVED; * ALL RIGHTS RESERVED;
* *
@ -90,7 +90,7 @@ soundex_code(char letter)
*/ */
#define MAX_LEVENSHTEIN_STRLEN 255 #define MAX_LEVENSHTEIN_STRLEN 255
static int levenshtein_internal(const char *s, const char *t, static int levenshtein_internal(text *s, text *t,
int ins_c, int del_c, int sub_c); int ins_c, int del_c, int sub_c);
@ -191,7 +191,7 @@ getcode(char c)
* cases, but your mileage may vary. * cases, but your mileage may vary.
*/ */
static int static int
levenshtein_internal(const char *s, const char *t, levenshtein_internal(text *s, text *t,
int ins_c, int del_c, int sub_c) int ins_c, int del_c, int sub_c)
{ {
int m, int m,
@ -203,8 +203,8 @@ levenshtein_internal(const char *s, const char *t,
const char *x; const char *x;
const char *y; const char *y;
m = strlen(s); m = VARSIZE_ANY_EXHDR(s);
n = strlen(t); n = VARSIZE_ANY_EXHDR(t);
/* /*
* We can transform an empty s into t with n insertions, or a non-empty t * We can transform an empty s into t with n insertions, or a non-empty t
@ -244,7 +244,7 @@ levenshtein_internal(const char *s, const char *t,
prev[i] = i * del_c; prev[i] = i * del_c;
/* Loop through rows of the notional array */ /* Loop through rows of the notional array */
for (y = t, j = 1; j < n; y++, j++) for (y = VARDATA_ANY(t), j = 1; j < n; y++, j++)
{ {
int *temp; int *temp;
@ -254,7 +254,7 @@ levenshtein_internal(const char *s, const char *t,
*/ */
curr[0] = j * ins_c; curr[0] = j * ins_c;
for (x = s, i = 1; i < m; x++, i++) for (x = VARDATA_ANY(s), i = 1; i < m; x++, i++)
{ {
int ins; int ins;
int del; int del;
@ -288,8 +288,8 @@ PG_FUNCTION_INFO_V1(levenshtein_with_costs);
Datum Datum
levenshtein_with_costs(PG_FUNCTION_ARGS) levenshtein_with_costs(PG_FUNCTION_ARGS)
{ {
char *src = TextDatumGetCString(PG_GETARG_DATUM(0)); text *src = PG_GETARG_TEXT_PP(0);
char *dst = TextDatumGetCString(PG_GETARG_DATUM(1)); text *dst = PG_GETARG_TEXT_PP(1);
int ins_c = PG_GETARG_INT32(2); int ins_c = PG_GETARG_INT32(2);
int del_c = PG_GETARG_INT32(3); int del_c = PG_GETARG_INT32(3);
int sub_c = PG_GETARG_INT32(4); int sub_c = PG_GETARG_INT32(4);
@ -302,8 +302,8 @@ PG_FUNCTION_INFO_V1(levenshtein);
Datum Datum
levenshtein(PG_FUNCTION_ARGS) levenshtein(PG_FUNCTION_ARGS)
{ {
char *src = TextDatumGetCString(PG_GETARG_DATUM(0)); text *src = PG_GETARG_TEXT_PP(0);
char *dst = TextDatumGetCString(PG_GETARG_DATUM(1)); text *dst = PG_GETARG_TEXT_PP(1);
PG_RETURN_INT32(levenshtein_internal(src, dst, 1, 1, 1)); PG_RETURN_INT32(levenshtein_internal(src, dst, 1, 1, 1));
} }