summaryrefslogtreecommitdiffstats
path: root/storage/myisam/ft_nlq_search.c
blob: 90a509057cf10e6f2e862e25784388d2df8a2eef (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
/* Copyright (c) 2001, 2011, Oracle and/or its affiliates.

   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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */

/* Written by Sergei A. Golubchik, who has a shared copyright to this code */

#define FT_CORE
#include "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;
  MI_INFO  *info;
  int       ndocs;
  int       curdoc;
  FT_DOC    doc[1];
};

typedef struct st_all_in_one
{
  MI_INFO    *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	       keylen, doc_cnt;
  FT_SUPERDOC  sdoc, *sptr;
  TREE_ELEMENT *selem;
  double       gweight=1;
  MI_INFO      *info=aio->info;
  MYISAM_SHARE *share= info->s;
  uchar        *keybuff=aio->keybuff;
  MI_KEYDEF    *keyinfo=info->s->keyinfo+aio->keynr;
  my_off_t     key_root;
  uint         extra= HA_FT_WLEN + info->s->rec_reflength;
  float tmp_weight;
  DBUG_ENTER("walk_and_match");

  word->weight=LWS_FOR_QUERY;

  keylen=_ft_make_key(info,aio->keynr,keybuff,word,0);
  keylen-=HA_FT_WLEN;
  doc_cnt=0;
  subkeys.i= 0;

  if (share->concurrent_insert)
    mysql_rwlock_rdlock(&share->key_root_lock[aio->keynr]);

  key_root= share->state.key_root[aio->keynr];

  /* Skip rows inserted by current inserted */
  for (r=_mi_search(info, keyinfo, keybuff, keylen, SEARCH_FIND, key_root) ;
       !r &&
         (subkeys.i= ft_sintXkorr(info->lastkey+info->lastkey_length-extra)) > 0 &&
         info->lastpos >= info->state->data_file_length ;
       r= _mi_search_next(info, keyinfo, info->lastkey,
                          info->lastkey_length, SEARCH_BIGGER, key_root))
    ;

  if (share->concurrent_insert)
    mysql_rwlock_unlock(&share->key_root_lock[aio->keynr]);

  info->update|= HA_STATE_AKTIV;              /* for _mi_test_if_changed() */

  /* The following should be safe, even if we compare doubles */
  while (!r && gweight)
  {

    if (keylen &&
        ha_compare_word(aio->charset,
                        info->lastkey + 1,
                        info->lastkey_length - extra - 1,
                        keybuff + 1, keylen - 1))
     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+=keylen;
      keyinfo=& info->s->ft2_keyinfo;
      key_root=info->lastpos;
      keylen=0;
      if (share->concurrent_insert)
        mysql_rwlock_rdlock(&share->key_root_lock[aio->keynr]);
      r=_mi_search_first(info, keyinfo, key_root);
      goto do_skip;
    }
    /* The weight we read was actually a float */
    tmp_weight= subkeys.f;
  /* 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->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 (share->concurrent_insert)
      mysql_rwlock_rdlock(&share->key_root_lock[aio->keynr]);

    if (_mi_test_if_changed(info) == 0)
	r=_mi_search_next(info, keyinfo, info->lastkey, info->lastkey_length,
                          SEARCH_BIGGER, key_root);
    else
	r=_mi_search(info, keyinfo, info->lastkey, info->lastkey_length,
                     SEARCH_BIGGER, key_root);
do_skip:
    while ((subkeys.i= ft_sintXkorr(info->lastkey+info->lastkey_length-extra)) > 0 &&
           !r && info->lastpos >= info->state->data_file_length)
      r= _mi_search_next(info, keyinfo, info->lastkey, info->lastkey_length,
                         SEARCH_BIGGER, key_root);

    if (share->concurrent_insert)
      mysql_rwlock_unlock(&share->key_root_lock[aio->keynr]);
  }
  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 *ft_init_nlq_search(MI_INFO *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;
  my_off_t    saved_lastpos=info->lastpos;
  struct st_mysql_ftparser *parser;
  MYSQL_FTPARSER_PARAM *ftparser_param;
  DBUG_ENTER("ft_init_nlq_search");

/* black magic ON */
  if ((int) (keynr = _mi_check_index(info,keynr)) < 0)
    DBUG_RETURN(NULL);
  if (_mi_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+info->s->base.max_key_length;
  parser= info->s->keyinfo[keynr].parser;
  if (! (ftparser_param= 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,
            NULL, NULL, MYF(0));

  ft_parse_init(&wtree, aio.charset);
  ftparser_param->flags= 0;
  if (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,docid,record))
      {
        info->update|= HA_STATE_AKTIV;
        ftparser_param->flags= MYSQL_FTFLAGS_NEED_COPY;
        if (unlikely(_mi_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(mi_key_memory_FT_INFO, sizeof(FT_INFO)+
			     sizeof(FT_DOC)*
			     (int)(aio.dtree.elements_in_tree-1),
			     MYF(0));
  if (!dlist)
    goto err;

  dlist->please= (struct _ft_vft *) & _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, 0);
  delete_tree(&wtree, 0);
  info->lastpos=saved_lastpos;
  DBUG_RETURN(dlist);
}


int ft_nlq_read_next(FT_INFO *handler, char *record)
{
  MI_INFO *info= (MI_INFO *) 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->lastpos=handler->doc[handler->curdoc].dpos;
  if (!(*info->read_record)(info,info->lastpos,(uchar*) record))
  {
    info->update|= HA_STATE_AKTIV;		/* Record is read */
    return 0;
  }
  return my_errno;
}


float ft_nlq_find_relevance(FT_INFO *handler,
			    uchar *record __attribute__((unused)),
			    uint length __attribute__((unused)))
{
  int a,b,c;
  FT_DOC  *docs=handler->doc;
  my_off_t docid=handler->info->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 ft_nlq_close_search(FT_INFO *handler)
{
  my_free(handler);
}


float ft_nlq_get_relevance(FT_INFO *handler)
{
  return (float) handler->doc[handler->curdoc].weight;
}


void ft_nlq_reinit_search(FT_INFO *handler)
{
  handler->curdoc=-1;
}