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/* Copyright (C) 2006 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; version 2 of the License.
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 */
#define FT_CORE
#include "ma_ftdefs.h"
/* search with natural language queries */
typedef struct ft_doc_rec
{
my_off_t dpos;
double weight;
} FT_DOC;
struct st_ft_info
{
struct _ft_vft *please;
MARIA_HA *info;
int ndocs;
int curdoc;
FT_DOC doc[1];
};
typedef struct st_all_in_one
{
MARIA_HA *info;
uint keynr;
CHARSET_INFO *charset;
uchar *keybuff;
TREE dtree;
} ALL_IN_ONE;
typedef struct st_ft_superdoc
{
FT_DOC doc;
FT_WORD *word_ptr;
double tmp_weight;
} FT_SUPERDOC;
static int FT_SUPERDOC_cmp(void* cmp_arg __attribute__((unused)),
FT_SUPERDOC *p1, FT_SUPERDOC *p2)
{
if (p1->doc.dpos < p2->doc.dpos)
return -1;
if (p1->doc.dpos == p2->doc.dpos)
return 0;
return 1;
}
static int walk_and_match(FT_WORD *word, uint32 count, ALL_IN_ONE *aio)
{
FT_WEIGTH subkeys;
int r;
uint doc_cnt;
FT_SUPERDOC sdoc, *sptr;
TREE_ELEMENT *selem;
double gweight=1;
MARIA_HA *info= aio->info;
uchar *keybuff= aio->keybuff;
MARIA_KEYDEF *keyinfo= info->s->keyinfo+aio->keynr;
my_off_t key_root=info->s->state.key_root[aio->keynr];
uint extra=HA_FT_WLEN+info->s->base.rec_reflength;
MARIA_KEY key;
#if HA_FT_WTYPE == HA_KEYTYPE_FLOAT
float tmp_weight;
#else
#error
#endif
DBUG_ENTER("walk_and_match");
word->weight=LWS_FOR_QUERY;
_ma_ft_make_key(info, &key, aio->keynr, keybuff, word, 0);
key.data_length-= HA_FT_WLEN;
doc_cnt=0;
/* Skip rows inserted by current inserted */
for (r= _ma_search(info, &key, SEARCH_FIND, key_root) ;
!r &&
(subkeys.i= ft_sintXkorr(info->last_key.data +
info->last_key.data_length +
info->last_key.ref_length - extra)) > 0 &&
info->cur_row.lastpos >= info->state->data_file_length ;
r= _ma_search_next(info, &info->last_key, SEARCH_BIGGER, key_root))
;
info->update|= HA_STATE_AKTIV; /* for _ma_test_if_changed() */
/* The following should be safe, even if we compare doubles */
while (!r && gweight)
{
if (key.data_length &&
ha_compare_text(aio->charset,
info->last_key.data+1,
info->last_key.data_length +
info->last_key.ref_length - extra - 1,
key.data+1, key.data_length-1, 0, 0))
break;
if (subkeys.i < 0)
{
if (doc_cnt)
DBUG_RETURN(1); /* index is corrupted */
/*
TODO here: unsafe optimization, should this word
be skipped (based on subkeys) ?
*/
keybuff+= key.data_length;
keyinfo= &info->s->ft2_keyinfo;
key_root= info->cur_row.lastpos;
key.data_length= 0;
r= _ma_search_first(info, keyinfo, key_root);
goto do_skip;
}
#if HA_FT_WTYPE == HA_KEYTYPE_FLOAT
/* The weight we read was actually a float */
tmp_weight= subkeys.f;
#else
#error
#endif
/* The following should be safe, even if we compare doubles */
if (tmp_weight==0)
DBUG_RETURN(doc_cnt); /* stopword, doc_cnt should be 0 */
sdoc.doc.dpos= info->cur_row.lastpos;
/* saving document matched into dtree */
if (!(selem=tree_insert(&aio->dtree, &sdoc, 0, aio->dtree.custom_arg)))
DBUG_RETURN(1);
sptr=(FT_SUPERDOC *)ELEMENT_KEY((&aio->dtree), selem);
if (selem->count==1) /* document's first match */
sptr->doc.weight=0;
else
sptr->doc.weight+=sptr->tmp_weight*sptr->word_ptr->weight;
sptr->word_ptr=word;
sptr->tmp_weight=tmp_weight;
doc_cnt++;
gweight=word->weight*GWS_IN_USE;
if (gweight < 0 || doc_cnt > 2000000)
gweight=0;
if (_ma_test_if_changed(info) == 0)
r= _ma_search_next(info, &info->last_key, SEARCH_BIGGER, key_root);
else
r= _ma_search(info, &info->last_key, SEARCH_BIGGER, key_root);
do_skip:
while ((subkeys.i= ft_sintXkorr(info->last_key.data +
info->last_key.data_length +
info->last_key.ref_length - extra)) > 0 &&
!r && info->cur_row.lastpos >= info->state->data_file_length)
r= _ma_search_next(info, &info->last_key, SEARCH_BIGGER, key_root);
}
word->weight=gweight;
DBUG_RETURN(0);
}
static int walk_and_copy(FT_SUPERDOC *from,
uint32 count __attribute__((unused)), FT_DOC **to)
{
DBUG_ENTER("walk_and_copy");
from->doc.weight+=from->tmp_weight*from->word_ptr->weight;
(*to)->dpos=from->doc.dpos;
(*to)->weight=from->doc.weight;
(*to)++;
DBUG_RETURN(0);
}
static int walk_and_push(FT_SUPERDOC *from,
uint32 count __attribute__((unused)), QUEUE *best)
{
DBUG_ENTER("walk_and_copy");
from->doc.weight+=from->tmp_weight*from->word_ptr->weight;
set_if_smaller(best->elements, ft_query_expansion_limit-1);
queue_insert(best, (uchar *)& from->doc);
DBUG_RETURN(0);
}
static int FT_DOC_cmp(void *unused __attribute__((unused)),
FT_DOC *a, FT_DOC *b)
{
return CMP_NUM(b->weight, a->weight);
}
FT_INFO *maria_ft_init_nlq_search(MARIA_HA *info, uint keynr, uchar *query,
uint query_len, uint flags, uchar *record)
{
TREE wtree;
ALL_IN_ONE aio;
FT_DOC *dptr;
FT_INFO *dlist=NULL;
MARIA_RECORD_POS saved_lastpos= info->cur_row.lastpos;
struct st_mysql_ftparser *parser;
MYSQL_FTPARSER_PARAM *ftparser_param;
DBUG_ENTER("maria_ft_init_nlq_search");
/* black magic ON */
if ((int) (keynr = _ma_check_index(info,keynr)) < 0)
DBUG_RETURN(NULL);
if (_ma_readinfo(info,F_RDLCK,1))
DBUG_RETURN(NULL);
/* black magic OFF */
aio.info=info;
aio.keynr=keynr;
aio.charset=info->s->keyinfo[keynr].seg->charset;
aio.keybuff= info->lastkey_buff2;
parser= info->s->keyinfo[keynr].parser;
if (! (ftparser_param= maria_ftparser_call_initializer(info, keynr, 0)))
goto err;
bzero(&wtree,sizeof(wtree));
init_tree(&aio.dtree,0,0,sizeof(FT_SUPERDOC),(qsort_cmp2)&FT_SUPERDOC_cmp,0,
NULL, NULL);
maria_ft_parse_init(&wtree, aio.charset);
ftparser_param->flags= 0;
if (maria_ft_parse(&wtree, query, query_len, parser, ftparser_param,
&wtree.mem_root))
goto err;
if (tree_walk(&wtree, (tree_walk_action)&walk_and_match, &aio,
left_root_right))
goto err;
if (flags & FT_EXPAND && ft_query_expansion_limit)
{
QUEUE best;
init_queue(&best,ft_query_expansion_limit,0,0, (queue_compare) &FT_DOC_cmp,
0, 0, 0);
tree_walk(&aio.dtree, (tree_walk_action) &walk_and_push,
&best, left_root_right);
while (best.elements)
{
my_off_t docid= ((FT_DOC *)queue_remove_top(&best))->dpos;
if (!(*info->read_record)(info, record, docid))
{
info->update|= HA_STATE_AKTIV;
ftparser_param->flags= MYSQL_FTFLAGS_NEED_COPY;
if (unlikely(_ma_ft_parse(&wtree, info, keynr, record, ftparser_param,
&wtree.mem_root)))
{
delete_queue(&best);
goto err;
}
}
}
delete_queue(&best);
reset_tree(&aio.dtree);
if (tree_walk(&wtree, (tree_walk_action)&walk_and_match, &aio,
left_root_right))
goto err;
}
/*
If ndocs == 0, this will not allocate RAM for FT_INFO.doc[],
so if ndocs == 0, FT_INFO.doc[] must not be accessed.
*/
dlist=(FT_INFO *)my_malloc(sizeof(FT_INFO)+
sizeof(FT_DOC)*
(int)(aio.dtree.elements_in_tree-1),
MYF(0));
if (!dlist)
goto err;
dlist->please= (struct _ft_vft *) & _ma_ft_vft_nlq;
dlist->ndocs=aio.dtree.elements_in_tree;
dlist->curdoc=-1;
dlist->info=aio.info;
dptr=dlist->doc;
tree_walk(&aio.dtree, (tree_walk_action) &walk_and_copy,
&dptr, left_root_right);
if (flags & FT_SORTED)
my_qsort2(dlist->doc, dlist->ndocs, sizeof(FT_DOC),
(qsort2_cmp)&FT_DOC_cmp, 0);
err:
delete_tree(&aio.dtree);
delete_tree(&wtree);
info->cur_row.lastpos= saved_lastpos;
DBUG_RETURN(dlist);
}
int maria_ft_nlq_read_next(FT_INFO *handler, char *record)
{
MARIA_HA *info= (MARIA_HA *) handler->info;
if (++handler->curdoc >= handler->ndocs)
{
--handler->curdoc;
return HA_ERR_END_OF_FILE;
}
info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
info->cur_row.lastpos= handler->doc[handler->curdoc].dpos;
if (!(*info->read_record)(info, (uchar *) record, info->cur_row.lastpos))
{
info->update|= HA_STATE_AKTIV; /* Record is read */
return 0;
}
return my_errno;
}
float maria_ft_nlq_find_relevance(FT_INFO *handler,
uchar *record __attribute__((unused)),
uint length __attribute__((unused)))
{
int a,b,c;
FT_DOC *docs=handler->doc;
MARIA_RECORD_POS docid= handler->info->cur_row.lastpos;
if (docid == HA_POS_ERROR)
return -5.0;
/* Assuming docs[] is sorted by dpos... */
for (a=0, b=handler->ndocs, c=(a+b)/2; b-a>1; c=(a+b)/2)
{
if (docs[c].dpos > docid)
b=c;
else
a=c;
}
/* bounds check to avoid accessing unallocated handler->doc */
if (a < handler->ndocs && docs[a].dpos == docid)
return (float) docs[a].weight;
else
return 0.0;
}
void maria_ft_nlq_close_search(FT_INFO *handler)
{
my_free(handler);
}
float maria_ft_nlq_get_relevance(FT_INFO *handler)
{
return (float) handler->doc[handler->curdoc].weight;
}
void maria_ft_nlq_reinit_search(FT_INFO *handler)
{
handler->curdoc=-1;
}
|