mirror/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-01-30 18:41:56 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions
mariadb/myisam/ft_boolean_search.c
monty@mysql.com ebc3b3afac BTREE-indexes in HEAP tables can now be used to optimize ORDER BY 
Don't read character set files if we are using only the default charset. In most cases the user will not anymore get a warning about missing character set files
Compare strings with space extend instead of space strip. Now the following comparisons holds:  "a" == "a " and "a\t" < "a". (Bug #3152).
Note: Because of the above fix, one has to do a REPAIR on any table that has an ascii character < 32 last in a CHAR/VARCHAR/TEXT columns.
2004-03-25 15:05:01 +02:00

690 lines
19 KiB
C
Raw Blame History

/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/* Written by Sergei A. Golubchik, who has a shared copyright to this code */
/* TODO: add caching - pre-read several index entries at once */
#define FT_CORE
#include "ftdefs.h"
/* search with boolean queries */
static double _wghts[11]=
{
0.131687242798354,
0.197530864197531,
0.296296296296296,
0.444444444444444,
0.666666666666667,
1.000000000000000,
1.500000000000000,
2.250000000000000,
3.375000000000000,
5.062500000000000,
7.593750000000000};
static double *wghts=_wghts+5; /* wghts[i] = 1.5**i */
static double _nwghts[11]=
{
-0.065843621399177,
-0.098765432098766,
-0.148148148148148,
-0.222222222222222,
-0.333333333333334,
-0.500000000000000,
-0.750000000000000,
-1.125000000000000,
-1.687500000000000,
-2.531250000000000,
-3.796875000000000};
static double *nwghts=_nwghts+5; /* nwghts[i] = -0.5*1.5**i */
#define FTB_FLAG_TRUNC 1 /* MUST be 1 */
#define FTB_FLAG_YES 2 /* no two from these three */
#define FTB_FLAG_NO 4 /* YES, NO, WONLY */
#define FTB_FLAG_WONLY 8 /* should be ever set both */
typedef struct st_ftb_expr FTB_EXPR;
struct st_ftb_expr
{
FTB_EXPR *up;
uint flags;
/* ^^^^^^^^^^^^^^^^^^ FTB_{EXPR,WORD} common section */
my_off_t docid[2];
float weight;
float cur_weight;
byte *quot, *qend;
uint yesses; /* number of "yes" words matched */
uint nos; /* number of "no" words matched */
uint ythresh; /* number of "yes" words in expr */
uint yweaks; /* number of "yes" words for scan only */
};
typedef struct st_ftb_word
{
FTB_EXPR *up;
uint flags;
/* ^^^^^^^^^^^^^^^^^^ FTB_{EXPR,WORD} common section */
my_off_t docid[2]; /* for index search and for scan */
my_off_t key_root;
MI_KEYDEF *keyinfo;
float weight;
uint ndepth;
uint len;
uchar off;
byte word[1];
} FTB_WORD;
typedef struct st_ft_info
{
struct _ft_vft *please;
MI_INFO *info;
CHARSET_INFO *charset;
FTB_EXPR *root;
FTB_WORD **list;
MEM_ROOT mem_root;
QUEUE queue;
TREE no_dupes;
my_off_t lastpos;
uint keynr;
uchar with_scan;
enum { UNINITIALIZED, READY, INDEX_SEARCH, INDEX_DONE } state;
} FTB;
static int FTB_WORD_cmp(my_off_t *v, FTB_WORD *a, FTB_WORD *b)
{
int i;
/* if a==curdoc, take it as a < b */
if (v && a->docid[0] == *v)
return -1;
/* ORDER BY docid, ndepth DESC */
i=CMP_NUM(a->docid[0], b->docid[0]);
if (!i)
i=CMP_NUM(b->ndepth,a->ndepth);
return i;
}
static int FTB_WORD_cmp_list(CHARSET_INFO *cs, FTB_WORD **a, FTB_WORD **b)
{
/* ORDER BY word DESC, ndepth DESC */
int i= mi_compare_text(cs, (uchar*) (*b)->word+1,(*b)->len-1,
(uchar*) (*a)->word+1,(*a)->len-1,0,0);
if (!i)
i=CMP_NUM((*b)->ndepth,(*a)->ndepth);
return i;
}
static void _ftb_parse_query(FTB *ftb, byte **start, byte *end,
FTB_EXPR *up, uint depth)
{
byte res;
FTB_PARAM param;
FT_WORD w;
FTB_WORD *ftbw;
FTB_EXPR *ftbe;
uint extra=HA_FT_WLEN+ftb->info->s->rec_reflength; /* just a shortcut */
if (ftb->state != UNINITIALIZED)
return;
param.prev=' ';
param.quot=up->quot;
while ((res=ft_get_word(ftb->charset,start,end,&w,&param)))
{
int r=param.plusminus;
float weight= (float) (param.pmsign ? nwghts : wghts)[(r>5)?5:((r<-5)?-5:r)];
switch (res) {
case 1: /* word found */
ftbw=(FTB_WORD *)alloc_root(&ftb->mem_root,
sizeof(FTB_WORD) +
(param.trunc ? MI_MAX_KEY_BUFF :
w.len+extra));
ftbw->len=w.len+1;
ftbw->flags=0;
if (param.yesno>0) ftbw->flags|=FTB_FLAG_YES;
if (param.yesno<0) ftbw->flags|=FTB_FLAG_NO;
if (param.trunc) ftbw->flags|=FTB_FLAG_TRUNC;
ftbw->weight=weight;
ftbw->up=up;
ftbw->docid[0]=ftbw->docid[1]=HA_POS_ERROR;
ftbw->ndepth= (param.yesno<0) + depth;
ftbw->key_root=HA_POS_ERROR;
memcpy(ftbw->word+1, w.pos, w.len);
ftbw->word[0]=w.len;
if (param.yesno > 0) up->ythresh++;
queue_insert(& ftb->queue, (byte *)ftbw);
ftb->with_scan|=(param.trunc & FTB_FLAG_TRUNC);
break;
case 2: /* left bracket */
ftbe=(FTB_EXPR *)alloc_root(&ftb->mem_root, sizeof(FTB_EXPR));
ftbe->flags=0;
if (param.yesno>0) ftbe->flags|=FTB_FLAG_YES;
if (param.yesno<0) ftbe->flags|=FTB_FLAG_NO;
ftbe->weight=weight;
ftbe->up=up;
ftbe->ythresh=ftbe->yweaks=0;
ftbe->docid[0]=ftbe->docid[1]=HA_POS_ERROR;
if ((ftbe->quot=param.quot)) ftb->with_scan|=2;
if (param.yesno > 0) up->ythresh++;
_ftb_parse_query(ftb, start, end, ftbe, depth+1);
param.quot=0;
break;
case 3: /* right bracket */
if (up->quot) up->qend=param.quot;
return;
}
}
return;
}
static int _ftb_no_dupes_cmp(void* not_used __attribute__((unused)),
const void *a,const void *b)
{
return CMP_NUM((*((my_off_t*)a)), (*((my_off_t*)b)));
}
/* returns 1 if the search was finished (must-word wasn't found) */
static int _ft2_search(FTB *ftb, FTB_WORD *ftbw, my_bool init_search)
{
int r;
uint off;
int subkeys;
MI_INFO *info=ftb->info;
if (init_search)
{
ftbw->key_root=info->s->state.key_root[ftb->keynr];
ftbw->keyinfo=info->s->keyinfo+ftb->keynr;
ftbw->off=0;
r=_mi_search(info, ftbw->keyinfo, (uchar*) ftbw->word, ftbw->len,
SEARCH_FIND | SEARCH_BIGGER, ftbw->key_root);
}
else
{
r=_mi_search(info, ftbw->keyinfo, (uchar*) ftbw->word+ftbw->off,
USE_WHOLE_KEY, SEARCH_BIGGER, ftbw->key_root);
}
if (!r && !ftbw->off)
{
r= mi_compare_text(ftb->charset,
info->lastkey + (ftbw->flags & FTB_FLAG_TRUNC),
ftbw->len - (ftbw->flags & FTB_FLAG_TRUNC),
(uchar*) ftbw->word + (ftbw->flags & FTB_FLAG_TRUNC),
ftbw->len - (ftbw->flags & FTB_FLAG_TRUNC),
0,0);
}
if (r) /* not found */
{
if (!ftbw->off || !(ftbw->flags & FTB_FLAG_TRUNC))
{
ftbw->docid[0]=HA_POS_ERROR;
if ((ftbw->flags & FTB_FLAG_YES) && ftbw->up->up==0)
{
/*
This word MUST BE present in every document returned,
so we can stop the search right now
*/
ftb->state=INDEX_DONE;
return 1; /* search is done */
}
else
return 0;
}
/* going up to the first-level tree to continue search there */
_mi_dpointer(info, (uchar*) (ftbw->word+ftbw->off+HA_FT_WLEN),
ftbw->key_root);
ftbw->key_root=info->s->state.key_root[ftb->keynr];
ftbw->keyinfo=info->s->keyinfo+ftb->keynr;
ftbw->off=0;
return _ft2_search(ftb, ftbw, 0);
}
/* matching key found */
memcpy(ftbw->word+ftbw->off, info->lastkey, info->lastkey_length);
if (!ftbw->off && (init_search || (ftbw->flags & FTB_FLAG_TRUNC)))
{
/* going down ? */
get_key_full_length_rdonly(off, info->lastkey);
subkeys=ft_sintXkorr(info->lastkey+off);
if (subkeys<0)
{
/* yep, going down, to the second-level tree */
/* TODO here: subkey-based optimization */
ftbw->off=off;
ftbw->key_root=info->lastpos;
ftbw->keyinfo=& info->s->ft2_keyinfo;
r=_mi_search_first(info, ftbw->keyinfo, ftbw->key_root);
DBUG_ASSERT(r==0); /* found something */
memcpy(ftbw->word+off, info->lastkey, info->lastkey_length);
}
}
ftbw->docid[0]=info->lastpos;
return 0;
}
static void _ftb_init_index_search(FT_INFO *ftb)
{
int i;
FTB_WORD *ftbw;
if ((ftb->state != READY && ftb->state !=INDEX_DONE) ||
ftb->keynr == NO_SUCH_KEY)
return;
ftb->state=INDEX_SEARCH;
for (i=ftb->queue.elements; i; i--)
{
ftbw=(FTB_WORD *)(ftb->queue.root[i]);
if (ftbw->flags & FTB_FLAG_TRUNC)
{
/*
special treatment for truncation operator
1. there are some (besides this) +words
| no need to search in the index, it can never ADD new rows
| to the result, and to remove half-matched rows we do scan anyway
2. -trunc*
| same as 1.
3. in 1 and 2, +/- need not be on the same expr. level,
but can be on any upper level, as in +word +(trunc1* trunc2*)
4. otherwise
| We have to index-search for this prefix.
| It may cause duplicates, as in the index (sorted by <word,docid>)
| <aaaa,row1>
| <aabb,row2>
| <aacc,row1>
| Searching for "aa*" will find row1 twice...
*/
FTB_EXPR *ftbe;
for (ftbe=(FTB_EXPR*)ftbw;
ftbe->up && !(ftbe->up->flags & FTB_FLAG_TRUNC);
ftbe->up->flags|= FTB_FLAG_TRUNC, ftbe=ftbe->up)
{
if (ftbe->flags & FTB_FLAG_NO || /* 2 */
ftbe->up->ythresh - ftbe->up->yweaks >1) /* 1 */
{
FTB_EXPR *top_ftbe=ftbe->up->up;
ftbw->docid[0]=HA_POS_ERROR;
for (ftbe=ftbw->up; ftbe != top_ftbe; ftbe=ftbe->up)
if (ftbe->flags & FTB_FLAG_YES)
ftbe->yweaks++;
ftbe=0;
break;
}
}
if (!ftbe)
continue;
/* 3 */
if (!is_tree_inited(& ftb->no_dupes))
init_tree(& ftb->no_dupes,0,0,sizeof(my_off_t),
_ftb_no_dupes_cmp,0,0,0);
else
reset_tree(& ftb->no_dupes);
}
if (_ft2_search(ftb, ftbw, 1))
return;
}
queue_fix(& ftb->queue);
}
FT_INFO * ft_init_boolean_search(MI_INFO *info, uint keynr, byte *query,
uint query_len)
{
FTB *ftb;
FTB_EXPR *ftbe;
uint res;
if (!(ftb=(FTB *)my_malloc(sizeof(FTB), MYF(MY_WME))))
return 0;
ftb->please= (struct _ft_vft *) & _ft_vft_boolean;
ftb->state=UNINITIALIZED;
ftb->info=info;
ftb->keynr=keynr;
ftb->charset= ((keynr==NO_SUCH_KEY) ?
default_charset_info : info->s->keyinfo[keynr].seg->charset);
ftb->with_scan=0;
ftb->lastpos=HA_POS_ERROR;
bzero(& ftb->no_dupes, sizeof(TREE));
init_alloc_root(&ftb->mem_root, 1024, 1024);
/*
Hack: instead of init_queue, we'll use reinit queue to be able
to alloc queue with alloc_root()
*/
res=ftb->queue.max_elements=1+query_len/(min(ft_min_word_len,2)+1);
if (!(ftb->queue.root=
(byte **)alloc_root(&ftb->mem_root, (res+1)*sizeof(void*))))
goto err;
reinit_queue(& ftb->queue, res, 0, 0,
(int (*)(void*,byte*,byte*))FTB_WORD_cmp, 0);
if (!(ftbe=(FTB_EXPR *)alloc_root(&ftb->mem_root, sizeof(FTB_EXPR))))
goto err;
ftbe->weight=1;
ftbe->flags=FTB_FLAG_YES;
ftbe->nos=1;
ftbe->quot=0;
ftbe->up=0;
ftbe->ythresh=ftbe->yweaks=0;
ftbe->docid[0]=ftbe->docid[1]=HA_POS_ERROR;
ftb->root=ftbe;
_ftb_parse_query(ftb, &query, query+query_len, ftbe, 0);
ftb->list=(FTB_WORD **)alloc_root(&ftb->mem_root,
sizeof(FTB_WORD *)*ftb->queue.elements);
memcpy(ftb->list, ftb->queue.root+1, sizeof(FTB_WORD *)*ftb->queue.elements);
qsort2(ftb->list, ftb->queue.elements, sizeof(FTB_WORD *),
(qsort2_cmp)FTB_WORD_cmp_list, ftb->charset);
if (ftb->queue.elements<2) ftb->with_scan &= ~FTB_FLAG_TRUNC;
ftb->state=READY;
return ftb;
err:
free_root(& ftb->mem_root, MYF(0));
my_free((gptr)ftb,MYF(0));
return 0;
}
/* returns 1 if str0 ~= /\<str1\>/ */
static int _ftb_strstr(const byte *s0, const byte *e0,
const byte *s1, const byte *e1,
CHARSET_INFO *cs)
{
const byte *p0, *p1;
my_bool s_after, e_before;
s_after=true_word_char(cs, s1[0]);
e_before=true_word_char(cs, e1[-1]);
p0=s0;
while (p0 < e0)
{
while (p0 < e0 && cs->to_upper[(uint) (uchar) *p0++] !=
cs->to_upper[(uint) (uchar) *s1])
/* no-op */;
if (p0 >= e0)
return 0;
if (s_after && p0-1 > s0 && true_word_char(cs, p0[-2]))
continue;
p1=s1+1;
while (p0 < e0 && p1 < e1 && cs->to_upper[(uint) (uchar) *p0] ==
cs->to_upper[(uint) (uchar) *p1])
p0++, p1++;
if (p1 == e1 && (!e_before || p0 == e0 || !true_word_char(cs, p0[0])))
return 1;
}
return 0;
}
static void _ftb_climb_the_tree(FTB *ftb, FTB_WORD *ftbw, FT_SEG_ITERATOR *ftsi_orig)
{
FT_SEG_ITERATOR ftsi;
FTB_EXPR *ftbe;
float weight=ftbw->weight;
int yn=ftbw->flags, ythresh, mode=(ftsi_orig != 0);
my_off_t curdoc=ftbw->docid[mode];
for (ftbe=ftbw->up; ftbe; ftbe=ftbe->up)
{
ythresh = ftbe->ythresh - (mode ? 0 : ftbe->yweaks);
if (ftbe->docid[mode] != curdoc)
{
ftbe->cur_weight=0;
ftbe->yesses=ftbe->nos=0;
ftbe->docid[mode]=curdoc;
}
if (ftbe->nos)
break;
if (yn & FTB_FLAG_YES)
{
weight /= ftbe->ythresh;
ftbe->cur_weight += weight;
if ((int) ++ftbe->yesses == ythresh)
{
yn=ftbe->flags;
weight=ftbe->cur_weight*ftbe->weight;
if (mode && ftbe->quot)
{
int not_found=1;
memcpy(&ftsi, ftsi_orig, sizeof(ftsi));
while (_mi_ft_segiterator(&ftsi) && not_found)
{
if (!ftsi.pos)
continue;
not_found = ! _ftb_strstr(ftsi.pos, ftsi.pos+ftsi.len,
ftbe->quot, ftbe->qend, ftb->charset);
}
if (not_found) break;
} /* ftbe->quot */
}
else
break;
}
else
if (yn & FTB_FLAG_NO)
{
/*
NOTE: special sort function of queue assures that all
(yn & FTB_FLAG_NO) != 0
events for every particular subexpression will
"auto-magically" happen BEFORE all the
(yn & FTB_FLAG_YES) != 0 events. So no
already matched expression can become not-matched again.
*/
++ftbe->nos;
break;
}
else
{
if (ftbe->ythresh)
weight/=3;
ftbe->cur_weight += weight;
if ((int) ftbe->yesses < ythresh)
break;
if (!(yn & FTB_FLAG_WONLY))
yn= ((int) ftbe->yesses++ == ythresh) ? ftbe->flags : FTB_FLAG_WONLY ;
weight*= ftbe->weight;
}
}
}
int ft_boolean_read_next(FT_INFO *ftb, char *record)
{
FTB_EXPR *ftbe;
FTB_WORD *ftbw;
MI_INFO *info=ftb->info;
my_off_t curdoc;
if (ftb->state != INDEX_SEARCH && ftb->state != INDEX_DONE)
return -1;
/* black magic ON */
if ((int) _mi_check_index(info, ftb->keynr) < 0)
return my_errno;
if (_mi_readinfo(info, F_RDLCK, 1))
return my_errno;
/* black magic OFF */
if (!ftb->queue.elements)
return my_errno=HA_ERR_END_OF_FILE;
/* Attention!!! Address of a local variable is used here! See err: label */
ftb->queue.first_cmp_arg=(void *)&curdoc;
while (ftb->state == INDEX_SEARCH &&
(curdoc=((FTB_WORD *)queue_top(& ftb->queue))->docid[0]) !=
HA_POS_ERROR)
{
while (curdoc == (ftbw=(FTB_WORD *)queue_top(& ftb->queue))->docid[0])
{
_ftb_climb_the_tree(ftb, ftbw, 0);
/* update queue */
_ft2_search(ftb, ftbw, 0);
queue_replaced(& ftb->queue);
}
ftbe=ftb->root;
if (ftbe->docid[0]==curdoc && ftbe->cur_weight>0 &&
ftbe->yesses>=(ftbe->ythresh-ftbe->yweaks) && !ftbe->nos)
{
/* curdoc matched ! */
if (is_tree_inited(&ftb->no_dupes) &&
tree_insert(&ftb->no_dupes, &curdoc, 0,
ftb->no_dupes.custom_arg)->count >1)
/* but it managed already to get past this line once */
continue;
info->lastpos=curdoc;
/* Clear all states, except that the table was updated */
info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
if (!(*info->read_record)(info,curdoc,record))
{
info->update|= HA_STATE_AKTIV; /* Record is read */
if (ftb->with_scan && ft_boolean_find_relevance(ftb,record,0)==0)
continue; /* no match */
my_errno=0;
goto err;
}
goto err;
}
}
ftb->state=INDEX_DONE;
my_errno=HA_ERR_END_OF_FILE;
err:
ftb->queue.first_cmp_arg=(void *)0;
return my_errno;
}
float ft_boolean_find_relevance(FT_INFO *ftb, byte *record, uint length)
{
FT_WORD word;
FTB_WORD *ftbw;
FTB_EXPR *ftbe;
FT_SEG_ITERATOR ftsi, ftsi2;
const byte *end;
my_off_t docid=ftb->info->lastpos;
if (docid == HA_POS_ERROR)
return -2.0;
if (!ftb->queue.elements)
return 0;
if (ftb->state != INDEX_SEARCH && docid <= ftb->lastpos)
{
FTB_EXPR *x;
uint i;
for (i=0; i < ftb->queue.elements; i++)
{
ftb->list[i]->docid[1]=HA_POS_ERROR;
for (x=ftb->list[i]->up; x; x=x->up)
x->docid[1]=HA_POS_ERROR;
}
}
ftb->lastpos=docid;
if (ftb->keynr==NO_SUCH_KEY)
_mi_ft_segiterator_dummy_init(record, length, &ftsi);
else
_mi_ft_segiterator_init(ftb->info, ftb->keynr, record, &ftsi);
memcpy(&ftsi2, &ftsi, sizeof(ftsi));
while (_mi_ft_segiterator(&ftsi))
{
if (!ftsi.pos)
continue;
end=ftsi.pos+ftsi.len;
while (ft_simple_get_word(ftb->charset,
(byte **) &ftsi.pos, (byte *) end, &word))
{
int a, b, c;
for (a=0, b=ftb->queue.elements, c=(a+b)/2; b-a>1; c=(a+b)/2)
{
ftbw=ftb->list[c];
if (mi_compare_text(ftb->charset, (uchar*) word.pos, word.len,
(uchar*) ftbw->word+1, ftbw->len-1,
(my_bool) (ftbw->flags&FTB_FLAG_TRUNC),0) >0)
b=c;
else
a=c;
}
for (; c>=0; c--)
{
ftbw=ftb->list[c];
if (mi_compare_text(ftb->charset, (uchar*) word.pos, word.len,
(uchar*) ftbw->word+1,ftbw->len-1,
(my_bool) (ftbw->flags&FTB_FLAG_TRUNC),0))
break;
if (ftbw->docid[1] == docid)
continue;
ftbw->docid[1]=docid;
_ftb_climb_the_tree(ftb, ftbw, &ftsi2);
}
}
}
ftbe=ftb->root;
if (ftbe->docid[1]==docid && ftbe->cur_weight>0 &&
ftbe->yesses>=ftbe->ythresh && !ftbe->nos)
{ /* row matched ! */
return ftbe->cur_weight;
}
else
{ /* match failed ! */
return 0.0;
}
}
void ft_boolean_close_search(FT_INFO *ftb)
{
if (is_tree_inited(& ftb->no_dupes))
{
delete_tree(& ftb->no_dupes);
}
free_root(& ftb->mem_root, MYF(0));
my_free((gptr)ftb,MYF(0));
}
float ft_boolean_get_relevance(FT_INFO *ftb)
{
return ftb->root->cur_weight;
}
void ft_boolean_reinit_search(FT_INFO *ftb)
{
_ftb_init_index_search(ftb);
}
Reference in a new issue View git blame Copy permalink