bigm_gin.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * Portions Copyright (c) 2017-2023, pg_bigm Development Group
   4  * Portions Copyright (c) 2013-2016, NTT DATA Corporation
   5  * Portions Copyright (c) 2007-2012, PostgreSQL Global Development Group
   6  *
   7  * Changelog:
   8  *       2013/01/09
   9  *       Support full text search using bigrams.
  10  *       Author: NTT DATA Corporation
  11  *
  12  *-------------------------------------------------------------------------
  13  */
  14 #include "postgres.h"
  15
  16 #include "bigm.h"
  17
  18 #include "access/gin.h"
  19 #include "access/gin_private.h"
  20 #include "access/itup.h"
  21 #include "access/skey.h"
  22 #include "access/tuptoaster.h"
  23 #if PG_VERSION_NUM > 90500
  24 #include "catalog/pg_am.h"
  25 #endif
  26 #include "catalog/pg_type.h"
  27 #include "funcapi.h"
  28 #include "mb/pg_wchar.h"
  29 #include "storage/bufmgr.h"
  30 #include "storage/bufpage.h"
  31 #include "tsearch/ts_locale.h"
  32 #include "utils/array.h"
  33 #include "utils/builtins.h"
  34 #include "utils/rel.h"
  35
  36
  37 PG_FUNCTION_INFO_V1(gin_extract_value_bigm);
  38 PG_FUNCTION_INFO_V1(gin_extract_query_bigm);
  39 PG_FUNCTION_INFO_V1(gin_bigm_consistent);
  40 PG_FUNCTION_INFO_V1(gin_bigm_compare_partial);
  41 PG_FUNCTION_INFO_V1(pg_gin_pending_stats);
  42
  43 /*
  44  * The function prototypes are created as a part of PG_FUNCTION_INFO_V1
  45  * macro since 9.4, and hence the declaration of the function prototypes
  46  * here is necessary only for 9.3 or before.
  47  */
  48 #if PG_VERSION_NUM < 90400
  49 Datum           gin_extract_value_bigm(PG_FUNCTION_ARGS);
  50 Datum           gin_extract_query_bigm(PG_FUNCTION_ARGS);
  51 Datum           gin_bigm_consistent(PG_FUNCTION_ARGS);
  52 Datum           gin_bigm_compare_partial(PG_FUNCTION_ARGS);
  53 Datum           pg_gin_pending_stats(PG_FUNCTION_ARGS);
  54 #endif
  55
  56 Datum
  57 gin_extract_value_bigm(PG_FUNCTION_ARGS)
  58 {
  59         text       *val = (text *) PG_GETARG_TEXT_P(0);
  60         int32      *nentries = (int32 *) PG_GETARG_POINTER(1);
  61         Datum      *entries = NULL;
  62         BIGM       *bgm;
  63         int32           bgmlen;
  64
  65         *nentries = 0;
  66
  67         bgm = generate_bigm(VARDATA(val), VARSIZE(val) - VARHDRSZ);
  68         bgmlen = ARRNELEM(bgm);
  69
  70         if (bgmlen > 0)
  71         {
  72                 bigm       *ptr;
  73                 int32           i;
  74
  75                 *nentries = bgmlen;
  76                 entries = (Datum *) palloc(sizeof(Datum) * bgmlen);
  77
  78                 ptr = GETARR(bgm);
  79                 for (i = 0; i < bgmlen; i++)
  80                 {
  81                         text       *item = cstring_to_text_with_len(ptr->str, ptr->bytelen);
  82
  83                         entries[i] = PointerGetDatum(item);
  84                         ptr++;
  85                 }
  86         }
  87
  88         PG_RETURN_POINTER(entries);
  89 }
  90
  91 Datum
  92 gin_extract_query_bigm(PG_FUNCTION_ARGS)
  93 {
  94         text       *val = (text *) PG_GETARG_TEXT_P(0);
  95         int32      *nentries = (int32 *) PG_GETARG_POINTER(1);
  96         StrategyNumber strategy = PG_GETARG_UINT16(2);
  97
  98         bool      **pmatch = (bool **) PG_GETARG_POINTER(3);
  99         Pointer   **extra_data = (Pointer **) PG_GETARG_POINTER(4);
 100
 101         /* bool   **nullFlags = (bool **) PG_GETARG_POINTER(5); */
 102         int32      *searchMode = (int32 *) PG_GETARG_POINTER(6);
 103         Datum      *entries = NULL;
 104         BIGM       *bgm;
 105         int32           bgmlen = 0;
 106         bigm       *ptr;
 107         int32           i;
 108         bool            removeDups;
 109
 110         switch (strategy)
 111         {
 112                 case LikeStrategyNumber:
 113                 {
 114                         char       *str = VARDATA(val);
 115                         int                     slen = VARSIZE(val) - VARHDRSZ;
 116                         bool       *recheck;
 117
 118                         /*
 119                          * For wildcard search we extract all the bigrams that every
 120                          * potentially-matching string must include.
 121                          */
 122                         bgm = generate_wildcard_bigm(str, slen, &removeDups);
 123                         bgmlen = ARRNELEM(bgm);
 124
 125                         /*
 126                          * Check whether the heap tuple fetched by index search needs to
 127                          * be rechecked against the query. If the search word consists of
 128                          * one or two characters and doesn't contain any space character,
 129                          * we can guarantee that the index test would be exact. That is,
 130                          * the heap tuple does match the query, so it doesn't need to be
 131                          * rechecked.
 132                          */
 133                         *extra_data = (Pointer *) palloc(sizeof(bool));
 134                         recheck = (bool *) *extra_data;
 135                         if (bgmlen == 1 && !removeDups)
 136                         {
 137                                 const char *sp;
 138
 139                                 *recheck = false;
 140                                 for (sp = str; (sp - str) < slen;)
 141                                 {
 142                                         if (t_isspace(sp))
 143                                         {
 144                                                 *recheck = true;
 145                                                 break;
 146                                         }
 147
 148                                         sp += IS_HIGHBIT_SET(*sp) ? pg_mblen(sp) : 1;
 149                                 }
 150                         }
 151                         else
 152                                 *recheck = true;
 153                         break;
 154                 }
 155                 case SimilarityStrategyNumber:
 156                 {
 157                         bgm = generate_bigm(VARDATA(val), VARSIZE(val) - VARHDRSZ);
 158                         bgmlen = ARRNELEM(bgm);
 159                         break;
 160                 }
 161                 default:
 162                         elog(ERROR, "unrecognized strategy number: %d", strategy);
 163                         bgm = NULL;                     /* keep compiler quiet */
 164                         break;
 165         }
 166
 167         *nentries = (bigm_gin_key_limit == 0) ?
 168                 bgmlen : Min(bigm_gin_key_limit, bgmlen);
 169         *pmatch = NULL;
 170
 171         if (*nentries > 0)
 172         {
 173                 entries = (Datum *) palloc(sizeof(Datum) * *nentries);
 174                 ptr = GETARR(bgm);
 175                 for (i = 0; i < *nentries; i++)
 176                 {
 177                         text       *item;
 178
 179                         if (ptr->pmatch)
 180                         {
 181                                 if (*pmatch == NULL)
 182                                         *pmatch = (bool *) palloc0(sizeof(bool) * *nentries);
 183                                 (*pmatch)[i] = true;
 184                         }
 185                         item = cstring_to_text_with_len(ptr->str, ptr->bytelen);
 186                         entries[i] = PointerGetDatum(item);
 187                         ptr++;
 188                 }
 189         }
 190
 191         /*
 192          * If no bigram was extracted then we have to scan all the index.
 193          */
 194         if (*nentries == 0)
 195                 *searchMode = GIN_SEARCH_MODE_ALL;
 196
 197         PG_RETURN_POINTER(entries);
 198 }
 199
 200 Datum
 201 gin_bigm_consistent(PG_FUNCTION_ARGS)
 202 {
 203         bool       *check = (bool *) PG_GETARG_POINTER(0);
 204         StrategyNumber strategy = PG_GETARG_UINT16(1);
 205
 206         /* text    *query = PG_GETARG_TEXT_P(2); */
 207         int32           nkeys = PG_GETARG_INT32(3);
 208
 209         Pointer    *extra_data = (Pointer *) PG_GETARG_POINTER(4);
 210         bool       *recheck = (bool *) PG_GETARG_POINTER(5);
 211         bool            res;
 212         int32           i;
 213         int32           ntrue;
 214
 215         switch (strategy)
 216         {
 217                 case LikeStrategyNumber:
 218
 219                         /*
 220                          * Don't recheck the heap tuple against the query if either
 221                          * pg_bigm.enable_recheck is disabled or the search word is the
 222                          * special one so that the index can return the exact result.
 223                          */
 224                         Assert(extra_data != NULL);
 225                         *recheck = bigm_enable_recheck &&
 226                                 (*((bool *) extra_data) || (nkeys != 1));
 227
 228                         /* Check if all extracted bigrams are presented. */
 229                         res = true;
 230                         for (i = 0; i < nkeys; i++)
 231                         {
 232                                 if (!check[i])
 233                                 {
 234                                         res = false;
 235                                         break;
 236                                 }
 237                         }
 238                         break;
 239                 case SimilarityStrategyNumber:
 240                         /* Count the matches */
 241                         *recheck = bigm_enable_recheck;
 242                         ntrue = 0;
 243                         for (i = 0; i < nkeys; i++)
 244                         {
 245                                 if (check[i])
 246                                         ntrue++;
 247                         }
 248 #ifdef DIVUNION
 249                         res = (nkeys == ntrue) ? true :
 250                                 ((((((float4) ntrue) / ((float4) (nkeys - ntrue)))) >=
 251                                   (float4) bigm_similarity_limit) ? true : false);
 252 #else
 253                         res = (nkeys == 0) ? false :
 254                                 ((((((float4) ntrue) / ((float4) nkeys))) >=
 255                                   (float4) bigm_similarity_limit) ? true : false);
 256 #endif
 257                         break;
 258                 default:
 259                         elog(ERROR, "unrecognized strategy number: %d", strategy);
 260                         res = false;            /* keep compiler quiet */
 261                         break;
 262         }
 263
 264         PG_RETURN_BOOL(res);
 265 }
 266
 267 Datum
 268 gin_bigm_compare_partial(PG_FUNCTION_ARGS)
 269 {
 270         text       *arg1 = PG_GETARG_TEXT_PP(0);
 271         text       *arg2 = PG_GETARG_TEXT_PP(1);
 272         char       *a1p;
 273         char       *a2p;
 274         int                     mblen1;
 275         int                     mblen2;
 276         int                     res;
 277
 278         a1p = VARDATA_ANY(arg1);
 279         a2p = VARDATA_ANY(arg2);
 280
 281         mblen1 = pg_mblen(a1p);
 282         mblen2 = pg_mblen(a2p);
 283
 284         if (mblen1 != mblen2)
 285                 PG_RETURN_INT32(1);
 286
 287         res = memcmp(a1p, a2p, mblen1) ? 1 : 0;
 288         PG_RETURN_INT32(res);
 289 }
 290
 291 /*
 292  * Report both number of pages and number of heap tuples that
 293  * are in the pending list.
 294  */
 295 Datum
 296 pg_gin_pending_stats(PG_FUNCTION_ARGS)
 297 {
 298         Oid                     indexOid = PG_GETARG_OID(0);
 299         Relation        indexRel;
 300         Buffer          metabuffer;
 301         Page            metapage;
 302         GinMetaPageData *metadata;
 303         Datum           values[2];
 304         bool            isnull[2];
 305         HeapTuple       tuple;
 306         TupleDesc       tupdesc;
 307
 308         indexRel = relation_open(indexOid, AccessShareLock);
 309
 310         if (indexRel->rd_rel->relkind != RELKIND_INDEX ||
 311                 indexRel->rd_rel->relam != GIN_AM_OID)
 312                 ereport(ERROR,
 313                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 314                                  errmsg("relation \"%s\" is not a GIN index",
 315                                                 RelationGetRelationName(indexRel))));
 316
 317         /*
 318          * Reject attempts to read non-local temporary relations; we would be
 319          * likely to get wrong data since we have no visibility into the owning
 320          * session's local buffers.
 321          */
 322         if (RELATION_IS_OTHER_TEMP(indexRel))
 323                 ereport(ERROR,
 324                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 325                                  errmsg("cannot access temporary indexes of other sessions")));
 326
 327         /*
 328          * Obtain statistic information from the meta page
 329          */
 330         metabuffer = ReadBuffer(indexRel, GIN_METAPAGE_BLKNO);
 331         LockBuffer(metabuffer, GIN_SHARE);
 332         metapage = BufferGetPage(metabuffer);
 333         metadata = GinPageGetMeta(metapage);
 334
 335         /*
 336          * Construct a tuple descriptor for the result row. This must match this
 337          * function's pg_bigm--x.x.sql entry.
 338          */
 339         tupdesc = CreateTemplateTupleDesc(2, false);
 340         TupleDescInitEntry(tupdesc, (AttrNumber) 1,
 341                                            "pages", INT4OID, -1, 0);
 342         TupleDescInitEntry(tupdesc, (AttrNumber) 2,
 343                                            "tuples", INT8OID, -1, 0);
 344         tupdesc = BlessTupleDesc(tupdesc);
 345
 346         /* pages */
 347         values[0] = Int32GetDatum(metadata->nPendingPages);
 348         isnull[0] = false;
 349
 350         /* tuples */
 351         values[1] = Int64GetDatum(metadata->nPendingHeapTuples);
 352         isnull[1] = false;
 353
 354         UnlockReleaseBuffer(metabuffer);
 355         relation_close(indexRel, AccessShareLock);
 356
 357         tuple = heap_form_tuple(tupdesc, values, isnull);
 358         PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
 359 }