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https://github.com/postgres/postgres.git
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d952373a98
This new header contains all the variable-length data types support (TOAST support) from postgres.h, which isn't needed by large parts of the backend code. Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://www.postgresql.org/message-id/flat/ddcce239-0f29-6e62-4b47-1f8ca742addf%40enterprisedb.com
361 lines
8.8 KiB
C
361 lines
8.8 KiB
C
/*
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* contrib/pg_trgm/trgm_gin.c
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*/
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#include "postgres.h"
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#include "access/gin.h"
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#include "access/stratnum.h"
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#include "fmgr.h"
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#include "trgm.h"
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#include "varatt.h"
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PG_FUNCTION_INFO_V1(gin_extract_trgm);
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PG_FUNCTION_INFO_V1(gin_extract_value_trgm);
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PG_FUNCTION_INFO_V1(gin_extract_query_trgm);
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PG_FUNCTION_INFO_V1(gin_trgm_consistent);
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PG_FUNCTION_INFO_V1(gin_trgm_triconsistent);
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/*
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* This function can only be called if a pre-9.1 version of the GIN operator
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* class definition is present in the catalogs (probably as a consequence
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* of upgrade-in-place). Cope.
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*/
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Datum
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gin_extract_trgm(PG_FUNCTION_ARGS)
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{
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if (PG_NARGS() == 3)
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return gin_extract_value_trgm(fcinfo);
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if (PG_NARGS() == 7)
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return gin_extract_query_trgm(fcinfo);
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elog(ERROR, "unexpected number of arguments to gin_extract_trgm");
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PG_RETURN_NULL();
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}
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Datum
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gin_extract_value_trgm(PG_FUNCTION_ARGS)
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{
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text *val = (text *) PG_GETARG_TEXT_PP(0);
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int32 *nentries = (int32 *) PG_GETARG_POINTER(1);
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Datum *entries = NULL;
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TRGM *trg;
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int32 trglen;
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*nentries = 0;
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trg = generate_trgm(VARDATA_ANY(val), VARSIZE_ANY_EXHDR(val));
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trglen = ARRNELEM(trg);
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if (trglen > 0)
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{
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trgm *ptr;
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int32 i;
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*nentries = trglen;
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entries = (Datum *) palloc(sizeof(Datum) * trglen);
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ptr = GETARR(trg);
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for (i = 0; i < trglen; i++)
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{
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int32 item = trgm2int(ptr);
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entries[i] = Int32GetDatum(item);
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ptr++;
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}
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}
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PG_RETURN_POINTER(entries);
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}
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Datum
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gin_extract_query_trgm(PG_FUNCTION_ARGS)
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{
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text *val = (text *) PG_GETARG_TEXT_PP(0);
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int32 *nentries = (int32 *) PG_GETARG_POINTER(1);
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StrategyNumber strategy = PG_GETARG_UINT16(2);
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/* bool **pmatch = (bool **) PG_GETARG_POINTER(3); */
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Pointer **extra_data = (Pointer **) PG_GETARG_POINTER(4);
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/* bool **nullFlags = (bool **) PG_GETARG_POINTER(5); */
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int32 *searchMode = (int32 *) PG_GETARG_POINTER(6);
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Datum *entries = NULL;
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TRGM *trg;
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int32 trglen;
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trgm *ptr;
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TrgmPackedGraph *graph;
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int32 i;
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switch (strategy)
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{
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case SimilarityStrategyNumber:
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case WordSimilarityStrategyNumber:
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case StrictWordSimilarityStrategyNumber:
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case EqualStrategyNumber:
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trg = generate_trgm(VARDATA_ANY(val), VARSIZE_ANY_EXHDR(val));
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break;
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case ILikeStrategyNumber:
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#ifndef IGNORECASE
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elog(ERROR, "cannot handle ~~* with case-sensitive trigrams");
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#endif
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/* FALL THRU */
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case LikeStrategyNumber:
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/*
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* For wildcard search we extract all the trigrams that every
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* potentially-matching string must include.
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*/
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trg = generate_wildcard_trgm(VARDATA_ANY(val),
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VARSIZE_ANY_EXHDR(val));
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break;
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case RegExpICaseStrategyNumber:
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#ifndef IGNORECASE
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elog(ERROR, "cannot handle ~* with case-sensitive trigrams");
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#endif
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/* FALL THRU */
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case RegExpStrategyNumber:
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trg = createTrgmNFA(val, PG_GET_COLLATION(),
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&graph, CurrentMemoryContext);
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if (trg && ARRNELEM(trg) > 0)
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{
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/*
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* Successful regex processing: store NFA-like graph as
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* extra_data. GIN API requires an array of nentries
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* Pointers, but we just put the same value in each element.
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*/
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trglen = ARRNELEM(trg);
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*extra_data = (Pointer *) palloc(sizeof(Pointer) * trglen);
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for (i = 0; i < trglen; i++)
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(*extra_data)[i] = (Pointer) graph;
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}
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else
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{
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/* No result: have to do full index scan. */
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*nentries = 0;
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*searchMode = GIN_SEARCH_MODE_ALL;
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PG_RETURN_POINTER(entries);
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}
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break;
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default:
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elog(ERROR, "unrecognized strategy number: %d", strategy);
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trg = NULL; /* keep compiler quiet */
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break;
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}
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trglen = ARRNELEM(trg);
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*nentries = trglen;
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if (trglen > 0)
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{
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entries = (Datum *) palloc(sizeof(Datum) * trglen);
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ptr = GETARR(trg);
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for (i = 0; i < trglen; i++)
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{
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int32 item = trgm2int(ptr);
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entries[i] = Int32GetDatum(item);
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ptr++;
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}
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}
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/*
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* If no trigram was extracted then we have to scan all the index.
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*/
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if (trglen == 0)
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*searchMode = GIN_SEARCH_MODE_ALL;
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PG_RETURN_POINTER(entries);
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}
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Datum
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gin_trgm_consistent(PG_FUNCTION_ARGS)
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{
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bool *check = (bool *) PG_GETARG_POINTER(0);
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StrategyNumber strategy = PG_GETARG_UINT16(1);
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/* text *query = PG_GETARG_TEXT_PP(2); */
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int32 nkeys = PG_GETARG_INT32(3);
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Pointer *extra_data = (Pointer *) PG_GETARG_POINTER(4);
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bool *recheck = (bool *) PG_GETARG_POINTER(5);
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bool res;
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int32 i,
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ntrue;
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double nlimit;
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/* All cases served by this function are inexact */
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*recheck = true;
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switch (strategy)
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{
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case SimilarityStrategyNumber:
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case WordSimilarityStrategyNumber:
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case StrictWordSimilarityStrategyNumber:
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nlimit = index_strategy_get_limit(strategy);
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/* Count the matches */
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ntrue = 0;
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for (i = 0; i < nkeys; i++)
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{
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if (check[i])
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ntrue++;
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}
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/*--------------------
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* If DIVUNION is defined then similarity formula is:
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* c / (len1 + len2 - c)
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* where c is number of common trigrams and it stands as ntrue in
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* this code. Here we don't know value of len2 but we can assume
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* that c (ntrue) is a lower bound of len2, so upper bound of
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* similarity is:
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* c / (len1 + c - c) => c / len1
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* If DIVUNION is not defined then similarity formula is:
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* c / max(len1, len2)
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* And again, c (ntrue) is a lower bound of len2, but c <= len1
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* just by definition and, consequently, upper bound of
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* similarity is just c / len1.
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* So, independently on DIVUNION the upper bound formula is the same.
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*/
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res = (nkeys == 0) ? false :
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(((((float4) ntrue) / ((float4) nkeys))) >= nlimit);
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break;
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case ILikeStrategyNumber:
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#ifndef IGNORECASE
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elog(ERROR, "cannot handle ~~* with case-sensitive trigrams");
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#endif
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/* FALL THRU */
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case LikeStrategyNumber:
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case EqualStrategyNumber:
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/* Check if all extracted trigrams are presented. */
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res = true;
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for (i = 0; i < nkeys; i++)
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{
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if (!check[i])
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{
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res = false;
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break;
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}
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}
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break;
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case RegExpICaseStrategyNumber:
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#ifndef IGNORECASE
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elog(ERROR, "cannot handle ~* with case-sensitive trigrams");
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#endif
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/* FALL THRU */
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case RegExpStrategyNumber:
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if (nkeys < 1)
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{
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/* Regex processing gave no result: do full index scan */
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res = true;
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}
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else
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res = trigramsMatchGraph((TrgmPackedGraph *) extra_data[0],
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check);
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break;
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default:
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elog(ERROR, "unrecognized strategy number: %d", strategy);
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res = false; /* keep compiler quiet */
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break;
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}
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PG_RETURN_BOOL(res);
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}
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/*
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* In all cases, GIN_TRUE is at least as favorable to inclusion as
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* GIN_MAYBE. If no better option is available, simply treat
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* GIN_MAYBE as if it were GIN_TRUE and apply the same test as the binary
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* consistent function.
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*/
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Datum
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gin_trgm_triconsistent(PG_FUNCTION_ARGS)
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{
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GinTernaryValue *check = (GinTernaryValue *) PG_GETARG_POINTER(0);
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StrategyNumber strategy = PG_GETARG_UINT16(1);
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/* text *query = PG_GETARG_TEXT_PP(2); */
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int32 nkeys = PG_GETARG_INT32(3);
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Pointer *extra_data = (Pointer *) PG_GETARG_POINTER(4);
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GinTernaryValue res = GIN_MAYBE;
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int32 i,
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ntrue;
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bool *boolcheck;
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double nlimit;
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switch (strategy)
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{
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case SimilarityStrategyNumber:
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case WordSimilarityStrategyNumber:
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case StrictWordSimilarityStrategyNumber:
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nlimit = index_strategy_get_limit(strategy);
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/* Count the matches */
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ntrue = 0;
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for (i = 0; i < nkeys; i++)
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{
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if (check[i] != GIN_FALSE)
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ntrue++;
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}
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/*
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* See comment in gin_trgm_consistent() about * upper bound
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* formula
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*/
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res = (nkeys == 0)
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? GIN_FALSE : (((((float4) ntrue) / ((float4) nkeys)) >= nlimit)
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? GIN_MAYBE : GIN_FALSE);
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break;
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case ILikeStrategyNumber:
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#ifndef IGNORECASE
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elog(ERROR, "cannot handle ~~* with case-sensitive trigrams");
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#endif
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/* FALL THRU */
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case LikeStrategyNumber:
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case EqualStrategyNumber:
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/* Check if all extracted trigrams are presented. */
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res = GIN_MAYBE;
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for (i = 0; i < nkeys; i++)
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{
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if (check[i] == GIN_FALSE)
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{
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res = GIN_FALSE;
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break;
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}
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}
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break;
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case RegExpICaseStrategyNumber:
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#ifndef IGNORECASE
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elog(ERROR, "cannot handle ~* with case-sensitive trigrams");
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#endif
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/* FALL THRU */
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case RegExpStrategyNumber:
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if (nkeys < 1)
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{
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/* Regex processing gave no result: do full index scan */
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res = GIN_MAYBE;
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}
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else
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{
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/*
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* As trigramsMatchGraph implements a monotonic boolean
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* function, promoting all GIN_MAYBE keys to GIN_TRUE will
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* give a conservative result.
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*/
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boolcheck = (bool *) palloc(sizeof(bool) * nkeys);
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for (i = 0; i < nkeys; i++)
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boolcheck[i] = (check[i] != GIN_FALSE);
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if (!trigramsMatchGraph((TrgmPackedGraph *) extra_data[0],
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boolcheck))
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res = GIN_FALSE;
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pfree(boolcheck);
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}
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break;
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default:
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elog(ERROR, "unrecognized strategy number: %d", strategy);
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res = GIN_FALSE; /* keep compiler quiet */
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break;
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}
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/* All cases served by this function are inexact */
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Assert(res != GIN_TRUE);
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PG_RETURN_GIN_TERNARY_VALUE(res);
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}
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