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CSC#4385: slow sorting for UTF8 large table:

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my_strnxfrm_utf8 now requires 2 bytes per character
in filesort key, instead of 3 bytes per character.
Shorter filesort keys make sorting faster.
This commit is contained in:
unknown
2005-01-26 16:34:09 +04:00
parent e8ae338356
commit 9bb464487d
20 changed files with 58 additions and 16 deletions
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37
strings/ctype-utf8.c
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@ -2238,6 +2238,12 @@ int my_wildcmp_utf8(CHARSET_INFO *cs,
}
static
uint my_strnxfrmlen_utf8(CHARSET_INFO *cs __attribute__((unused)), uint len)
{
return (len * 2 + 2) / 3;
}
static int my_strnxfrm_utf8(CHARSET_INFO *cs,
uchar *dst, uint dstlen,
const uchar *src, uint srclen)
@ -2245,29 +2251,33 @@ static int my_strnxfrm_utf8(CHARSET_INFO *cs,
my_wc_t wc;
int res;
int plane;
uchar *de = dst + dstlen;
uchar *de= dst + dstlen;
uchar *de_beg= de - 1;
const uchar *se = src + srclen;
while( src < se && dst < de )
while (dst < de_beg)
{
if ((res=my_utf8_uni(cs,&wc, src, se))<0)
{
if ((res=my_utf8_uni(cs,&wc, src, se)) <= 0)
break;
}
src+=res;
srclen-=res;
plane=(wc>>8) & 0xFF;
wc = uni_plane[plane] ? uni_plane[plane][wc & 0xFF].sort : wc;
if ((res=my_uni_utf8(cs,wc,dst,de)) <0)
{
break;
}
dst+=res;
*dst++= wc >> 8;
*dst++= wc & 0xFF;
}
if (dst < de)
bfill(dst, de - dst, ' ');
while (dst < de_beg) /* Fill the tail with keys for space character */
{
*dst++= 0x00;
*dst++= 0x20;
}
if (dst < de) /* Clear the last byte, if "dstlen" was an odd number */
*de= 0x00;
return dstlen;
}
@ -2306,6 +2316,7 @@ static MY_COLLATION_HANDLER my_collation_ci_handler =
my_strnncoll_utf8,
my_strnncollsp_utf8,
my_strnxfrm_utf8,
my_strnxfrmlen_utf8,
my_like_range_mb,
my_wildcmp_utf8,
my_strcasecmp_utf8,